<?xml version="1.0" encoding="us-ascii"?>
<!-- Created by Merrill Corporation -->
<!-- Generated by Fujitsu Interstage XWand B0189 -->
<!--Generated by IRIS XBRL Generation Engine-->
<link:linkbase xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt">
  <link:roleRef roleURI="http://www.mistrasgroup.com/role/DisclosureRelatedPartyTransactionsDetails" xlink:type="simple" xlink:href="mg-20130531.xsd#DisclosureRelatedPartyTransactionsDetails" />
  <link:roleRef roleURI="http://www.mistrasgroup.com/role/DisclosureIncomeTaxesDetails2" xlink:type="simple" xlink:href="mg-20130531.xsd#DisclosureIncomeTaxesDetails2" />
  <link:roleRef roleURI="http://www.mistrasgroup.com/role/DisclosureAcquisitionsDetails" xlink:type="simple" xlink:href="mg-20130531.xsd#DisclosureAcquisitionsDetails" />
  <link:roleRef roleURI="http://www.mistrasgroup.com/role/DisclosureSubsequentEventDetails" xlink:type="simple" xlink:href="mg-20130531.xsd#DisclosureSubsequentEventDetails" />
  <link:roleRef roleURI="http://www.mistrasgroup.com/role/DisclosurePropertyPlantAndEquipmentNetDetails" xlink:type="simple" xlink:href="mg-20130531.xsd#DisclosurePropertyPlantAndEquipmentNetDetails" />
  <link:roleRef roleURI="http://www.mistrasgroup.com/role/DisclosureLongTermDebtDetails" xlink:type="simple" xlink:href="mg-20130531.xsd#DisclosureLongTermDebtDetails" />
  <link:roleRef roleURI="http://www.mistrasgroup.com/role/DisclosureIntangibleAssetsDetails" xlink:type="simple" xlink:href="mg-20130531.xsd#DisclosureIntangibleAssetsDetails" />
  <link:roleRef roleURI="http://www.mistrasgroup.com/role/DisclosureObligationsUnderCapitalLeasesDetails" xlink:type="simple" xlink:href="mg-20130531.xsd#DisclosureObligationsUnderCapitalLeasesDetails" />
  <link:roleRef roleURI="http://www.mistrasgroup.com/role/DisclosureEmployeeBenefitPlansDetails" xlink:type="simple" xlink:href="mg-20130531.xsd#DisclosureEmployeeBenefitPlansDetails" />
  <link:roleRef roleURI="http://www.mistrasgroup.com/role/DisclosureSummaryOfSignificantAccountingPoliciesDetails" xlink:type="simple" xlink:href="mg-20130531.xsd#DisclosureSummaryOfSignificantAccountingPoliciesDetails" />
  <link:roleRef roleURI="http://www.mistrasgroup.com/role/DisclosureSegmentDisclosureDetails" xlink:type="simple" xlink:href="mg-20130531.xsd#DisclosureSegmentDisclosureDetails" />
  <link:roleRef roleURI="http://www.mistrasgroup.com/role/DisclosureFairValueMeasurementsDetails" xlink:type="simple" xlink:href="mg-20130531.xsd#DisclosureFairValueMeasurementsDetails" />
  <link:roleRef roleURI="http://www.mistrasgroup.com/role/DisclosureCapitalizationDetails2" xlink:type="simple" xlink:href="mg-20130531.xsd#DisclosureCapitalizationDetails2" />
  <link:roleRef roleURI="http://www.mistrasgroup.com/role/DisclosureCapitalizationDetails3" xlink:type="simple" xlink:href="mg-20130531.xsd#DisclosureCapitalizationDetails3" />
  <link:roleRef roleURI="http://www.mistrasgroup.com/role/DisclosureCapitalizationDetails5" xlink:type="simple" xlink:href="mg-20130531.xsd#DisclosureCapitalizationDetails5" />
  <link:roleRef roleURI="http://www.mistrasgroup.com/role/DisclosureCapitalizationDetails4" xlink:type="simple" xlink:href="mg-20130531.xsd#DisclosureCapitalizationDetails4" />
  <link:roleRef roleURI="http://www.mistrasgroup.com/role/DisclosureCommitmentsAndContingenciesDetails" xlink:type="simple" xlink:href="mg-20130531.xsd#DisclosureCommitmentsAndContingenciesDetails" />
  <link:roleRef roleURI="http://www.mistrasgroup.com/role/DisclosureSegmentDisclosureDetails2" xlink:type="simple" xlink:href="mg-20130531.xsd#DisclosureSegmentDisclosureDetails2" />
  <link:roleRef roleURI="http://www.mistrasgroup.com/role/DisclosureEarningsPerShareDetails" xlink:type="simple" xlink:href="mg-20130531.xsd#DisclosureEarningsPerShareDetails" />
  <link:roleRef roleURI="http://www.mistrasgroup.com/role/DisclosureSummaryOfSignificantAccountingPoliciesDetails2" xlink:type="simple" xlink:href="mg-20130531.xsd#DisclosureSummaryOfSignificantAccountingPoliciesDetails2" />
  <link:roleRef roleURI="http://www.mistrasgroup.com/role/DisclosureSegmentDisclosureDetails3" xlink:type="simple" xlink:href="mg-20130531.xsd#DisclosureSegmentDisclosureDetails3" />
  <link:roleRef roleURI="http://www.mistrasgroup.com/role/DisclosureGoodwillDetails" xlink:type="simple" xlink:href="mg-20130531.xsd#DisclosureGoodwillDetails" />
  <link:roleRef roleURI="http://www.mistrasgroup.com/role/DisclosureSummaryOfSignificantAccountingPoliciesDetails3" xlink:type="simple" xlink:href="mg-20130531.xsd#DisclosureSummaryOfSignificantAccountingPoliciesDetails3" />
  <link:roleRef roleURI="http://www.mistrasgroup.com/role/DisclosureEmployeeBenefitPlansDetails2" xlink:type="simple" xlink:href="mg-20130531.xsd#DisclosureEmployeeBenefitPlansDetails2" />
  <link:roleRef roleURI="http://www.mistrasgroup.com/role/StatementOfStockholdersEquity" xlink:type="simple" xlink:href="mg-20130531.xsd#StatementOfStockholdersEquity" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.mistrasgroup.com/role/DisclosureRelatedPartyTransactionsDetails">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="RelatedPartyTransactionLineItems" xlink:title="RelatedPartyTransactionLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:title="ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="RelatedPartyTransactionLineItems" xlink:to="ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:title="definition: RelatedPartyTransactionLineItems to ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" use="optional" order="1.0" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="RelatedPartyTransactionsByRelatedPartyAxis" xlink:title="RelatedPartyTransactionsByRelatedPartyAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:to="RelatedPartyTransactionsByRelatedPartyAxis" xlink:title="definition: ScheduleOfRelatedPartyTransactionsByRelatedPartyTable to RelatedPartyTransactionsByRelatedPartyAxis" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="RelatedPartyDomain" xlink:title="RelatedPartyDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="RelatedPartyDomain" xlink:title="definition: RelatedPartyTransactionsByRelatedPartyAxis to RelatedPartyDomain" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="RelatedPartyDomain_2" xlink:title="RelatedPartyDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="RelatedPartyDomain_2" xlink:title="definition: RelatedPartyTransactionsByRelatedPartyAxis to RelatedPartyDomain" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_ShareholderAndOfficerMember" xlink:label="ShareholderAndOfficerMember" xlink:title="ShareholderAndOfficerMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyDomain" xlink:to="ShareholderAndOfficerMember" xlink:title="definition: RelatedPartyDomain to ShareholderAndOfficerMember" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2013/dei-2013-01-31.xsd#dei_EntityByLocationAxis" xlink:label="EntityByLocationAxis" xlink:title="EntityByLocationAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:to="EntityByLocationAxis" xlink:title="definition: ScheduleOfRelatedPartyTransactionsByRelatedPartyTable to EntityByLocationAxis" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2013/dei-2013-01-31.xsd#dei_LocationDomain" xlink:label="LocationDomain" xlink:title="LocationDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="EntityByLocationAxis" xlink:to="LocationDomain" xlink:title="definition: EntityByLocationAxis to LocationDomain" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2013/dei-2013-01-31.xsd#dei_LocationDomain" xlink:label="LocationDomain_2" xlink:title="LocationDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="EntityByLocationAxis" xlink:to="LocationDomain_2" xlink:title="definition: EntityByLocationAxis to LocationDomain" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/country/2013/country-2013-01-31.xsd#country_FR" xlink:label="FR" xlink:title="FR" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LocationDomain" xlink:to="FR" xlink:title="definition: LocationDomain to FR" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_RelatedPartyTransactionRentPayments" xlink:label="RelatedPartyTransactionRentPayments" xlink:title="RelatedPartyTransactionRentPayments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="RelatedPartyTransactionRentPayments" xlink:title="definition: RelatedPartyTransactionLineItems to RelatedPartyTransactionRentPayments" use="optional" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://www.mistrasgroup.com/role/DisclosureIncomeTaxesDetails2">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_OperatingLossCarryforwardsLineItems" xlink:label="OperatingLossCarryforwardsLineItems" xlink:title="OperatingLossCarryforwardsLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_OperatingLossCarryforwardsTable" xlink:label="OperatingLossCarryforwardsTable" xlink:title="OperatingLossCarryforwardsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="OperatingLossCarryforwardsTable" xlink:title="definition: OperatingLossCarryforwardsLineItems to OperatingLossCarryforwardsTable" use="optional" order="1.0" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_IncomeTaxAuthorityAxis" xlink:label="IncomeTaxAuthorityAxis" xlink:title="IncomeTaxAuthorityAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="OperatingLossCarryforwardsTable" xlink:to="IncomeTaxAuthorityAxis" xlink:title="definition: OperatingLossCarryforwardsTable to IncomeTaxAuthorityAxis" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain" xlink:label="IncomeTaxAuthorityDomain" xlink:title="IncomeTaxAuthorityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="IncomeTaxAuthorityAxis" xlink:to="IncomeTaxAuthorityDomain" xlink:title="definition: IncomeTaxAuthorityAxis to IncomeTaxAuthorityDomain" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain" xlink:label="IncomeTaxAuthorityDomain_2" xlink:title="IncomeTaxAuthorityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="IncomeTaxAuthorityAxis" xlink:to="IncomeTaxAuthorityDomain_2" xlink:title="definition: IncomeTaxAuthorityAxis to IncomeTaxAuthorityDomain" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_StateAndLocalJurisdictionMember" xlink:label="StateAndLocalJurisdictionMember" xlink:title="StateAndLocalJurisdictionMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxAuthorityDomain" xlink:to="StateAndLocalJurisdictionMember" xlink:title="definition: IncomeTaxAuthorityDomain to StateAndLocalJurisdictionMember" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ForeignCountryMember" xlink:label="ForeignCountryMember" xlink:title="ForeignCountryMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxAuthorityDomain" xlink:to="ForeignCountryMember" xlink:title="definition: IncomeTaxAuthorityDomain to ForeignCountryMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_OperatingLossCarryforwards" xlink:label="OperatingLossCarryforwards" xlink:title="OperatingLossCarryforwards" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingLossCarryforwardsLineItems" xlink:to="OperatingLossCarryforwards" xlink:title="definition: OperatingLossCarryforwardsLineItems to OperatingLossCarryforwards" use="optional" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://www.mistrasgroup.com/role/DisclosureAcquisitionsDetails">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:label="BusinessAcquisitionLineItems" xlink:title="BusinessAcquisitionLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:label="ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:title="ScheduleOfBusinessAcquisitionsByAcquisitionTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="BusinessAcquisitionLineItems" xlink:to="ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:title="definition: BusinessAcquisitionLineItems to ScheduleOfBusinessAcquisitionsByAcquisitionTable" use="optional" order="1.0" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="BusinessAcquisitionAxis" xlink:title="BusinessAcquisitionAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:to="BusinessAcquisitionAxis" xlink:title="definition: ScheduleOfBusinessAcquisitionsByAcquisitionTable to BusinessAcquisitionAxis" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="BusinessAcquisitionAcquireeDomain" xlink:title="BusinessAcquisitionAcquireeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="BusinessAcquisitionAxis" xlink:to="BusinessAcquisitionAcquireeDomain" xlink:title="definition: BusinessAcquisitionAxis to BusinessAcquisitionAcquireeDomain" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="BusinessAcquisitionAcquireeDomain_2" xlink:title="BusinessAcquisitionAcquireeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="BusinessAcquisitionAxis" xlink:to="BusinessAcquisitionAcquireeDomain_2" xlink:title="definition: BusinessAcquisitionAxis to BusinessAcquisitionAcquireeDomain" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_AcquisitionsInFiscal2013Member" xlink:label="AcquisitionsInFiscal2013Member" xlink:title="AcquisitionsInFiscal2013Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionAcquireeDomain" xlink:to="AcquisitionsInFiscal2013Member" xlink:title="definition: BusinessAcquisitionAcquireeDomain to AcquisitionsInFiscal2013Member" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_AcquisitionsInFiscal2012Member" xlink:label="AcquisitionsInFiscal2012Member" xlink:title="AcquisitionsInFiscal2012Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionAcquireeDomain" xlink:to="AcquisitionsInFiscal2012Member" xlink:title="definition: BusinessAcquisitionAcquireeDomain to AcquisitionsInFiscal2012Member" use="optional" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember" xlink:label="SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember" xlink:title="SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionAcquireeDomain" xlink:to="SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember" xlink:title="definition: BusinessAcquisitionAcquireeDomain to SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_RangeAxis" xlink:label="RangeAxis" xlink:title="RangeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:to="RangeAxis" xlink:title="definition: ScheduleOfBusinessAcquisitionsByAcquisitionTable to RangeAxis" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_RangeMember" xlink:label="RangeMember" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RangeAxis" xlink:to="RangeMember" xlink:title="definition: RangeAxis to RangeMember" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_RangeMember" xlink:label="RangeMember_2" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RangeAxis" xlink:to="RangeMember_2" xlink:title="definition: RangeAxis to RangeMember" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_MinimumMember" xlink:label="MinimumMember" xlink:title="MinimumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MinimumMember" xlink:title="definition: RangeMember to MinimumMember" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_MaximumMember" xlink:label="MaximumMember" xlink:title="MaximumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MaximumMember" xlink:title="definition: RangeMember to MaximumMember" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="StatementBusinessSegmentsAxis" xlink:title="StatementBusinessSegmentsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:to="StatementBusinessSegmentsAxis" xlink:title="definition: ScheduleOfBusinessAcquisitionsByAcquisitionTable to StatementBusinessSegmentsAxis" use="optional" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_SegmentDomain" xlink:label="SegmentDomain" xlink:title="SegmentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementBusinessSegmentsAxis" xlink:to="SegmentDomain" xlink:title="definition: StatementBusinessSegmentsAxis to SegmentDomain" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_SegmentDomain" xlink:label="SegmentDomain_2" xlink:title="SegmentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementBusinessSegmentsAxis" xlink:to="SegmentDomain_2" xlink:title="definition: StatementBusinessSegmentsAxis to SegmentDomain" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_InternationalMember" xlink:label="InternationalMember" xlink:title="InternationalMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentDomain" xlink:to="InternationalMember" xlink:title="definition: SegmentDomain to InternationalMember" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_ServicesMember" xlink:label="ServicesMember" xlink:title="ServicesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentDomain" xlink:to="ServicesMember" xlink:title="definition: SegmentDomain to ServicesMember" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_ProductsAndSystemsMember" xlink:label="ProductsAndSystemsMember" xlink:title="ProductsAndSystemsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentDomain" xlink:to="ProductsAndSystemsMember" xlink:title="definition: SegmentDomain to ProductsAndSystemsMember" use="optional" order="8000.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired" xlink:label="BusinessAcquisitionPercentageOfVotingInterestsAcquired" xlink:title="BusinessAcquisitionPercentageOfVotingInterestsAcquired" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessAcquisitionPercentageOfVotingInterestsAcquired" xlink:title="definition: BusinessAcquisitionLineItems to BusinessAcquisitionPercentageOfVotingInterestsAcquired" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_BusinessCombinationContingentConsiderationPaymentPeriod" xlink:label="BusinessCombinationContingentConsiderationPaymentPeriod" xlink:title="BusinessCombinationContingentConsiderationPaymentPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessCombinationContingentConsiderationPaymentPeriod" xlink:title="definition: BusinessAcquisitionLineItems to BusinessCombinationContingentConsiderationPaymentPeriod" use="optional" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueLow" xlink:label="BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueLow" xlink:title="BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueLow" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueLow" xlink:title="definition: BusinessAcquisitionLineItems to BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueLow" use="optional" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh" xlink:label="BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh" xlink:title="BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh" xlink:title="definition: BusinessAcquisitionLineItems to BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh" use="optional" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_BusinessCombinationConsiderationTransferredDebtRepaymentTerm" xlink:label="BusinessCombinationConsiderationTransferredDebtRepaymentTerm" xlink:title="BusinessCombinationConsiderationTransferredDebtRepaymentTerm" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessCombinationConsiderationTransferredDebtRepaymentTerm" xlink:title="definition: BusinessAcquisitionLineItems to BusinessCombinationConsiderationTransferredDebtRepaymentTerm" use="optional" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract" xlink:label="BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract" xlink:title="BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract" xlink:title="definition: BusinessAcquisitionLineItems to BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_NumberOfBusinessesAcquired" xlink:label="NumberOfBusinessesAcquired" xlink:title="NumberOfBusinessesAcquired" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract" xlink:to="NumberOfBusinessesAcquired" xlink:title="definition: BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract to NumberOfBusinessesAcquired" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferredAbstract" xlink:label="BusinessCombinationConsiderationTransferredAbstract" xlink:title="BusinessCombinationConsiderationTransferredAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract" xlink:to="BusinessCombinationConsiderationTransferredAbstract" xlink:title="definition: BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract to BusinessCombinationConsiderationTransferredAbstract" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesGross" xlink:label="PaymentsToAcquireBusinessesGross" xlink:title="PaymentsToAcquireBusinessesGross" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationConsiderationTransferredAbstract" xlink:to="PaymentsToAcquireBusinessesGross" xlink:title="definition: BusinessCombinationConsiderationTransferredAbstract to PaymentsToAcquireBusinessesGross" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferredLiabilitiesIncurred" xlink:label="BusinessCombinationConsiderationTransferredLiabilitiesIncurred" xlink:title="BusinessCombinationConsiderationTransferredLiabilitiesIncurred" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationConsiderationTransferredAbstract" xlink:to="BusinessCombinationConsiderationTransferredLiabilitiesIncurred" xlink:title="definition: BusinessCombinationConsiderationTransferredAbstract to BusinessCombinationConsiderationTransferredLiabilitiesIncurred" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_BusinessCombinationContingentConsiderationLiability" xlink:label="BusinessCombinationContingentConsiderationLiability" xlink:title="BusinessCombinationContingentConsiderationLiability" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationConsiderationTransferredAbstract" xlink:to="BusinessCombinationContingentConsiderationLiability" xlink:title="definition: BusinessCombinationConsiderationTransferredAbstract to BusinessCombinationContingentConsiderationLiability" use="optional" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferred1" xlink:label="BusinessCombinationConsiderationTransferred1" xlink:title="BusinessCombinationConsiderationTransferred1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationConsiderationTransferredAbstract" xlink:to="BusinessCombinationConsiderationTransferred1" xlink:title="definition: BusinessCombinationConsiderationTransferredAbstract to BusinessCombinationConsiderationTransferred1" use="optional" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilities" xlink:label="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilities" xlink:title="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract" xlink:to="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilities" xlink:title="definition: BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract to BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilities" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDebtAndOtherLongTermLiabilities" xlink:label="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDebtAndOtherLongTermLiabilities" xlink:title="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDebtAndOtherLongTermLiabilities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract" xlink:to="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDebtAndOtherLongTermLiabilities" xlink:title="definition: BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract to BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDebtAndOtherLongTermLiabilities" use="optional" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" xlink:label="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" xlink:title="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract" xlink:to="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" xlink:title="definition: BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract to BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxAssetsLiabilities" xlink:label="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxAssetsLiabilities" xlink:title="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxAssetsLiabilities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract" xlink:to="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxAssetsLiabilities" xlink:title="definition: BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract to BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxAssetsLiabilities" use="optional" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles" xlink:label="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles" xlink:title="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract" xlink:to="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles" xlink:title="definition: BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract to BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_GoodwillAcquiredDuringPeriod" xlink:label="GoodwillAcquiredDuringPeriod" xlink:title="GoodwillAcquiredDuringPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract" xlink:to="GoodwillAcquiredDuringPeriod" xlink:title="definition: BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract to GoodwillAcquiredDuringPeriod" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedLessNoncontrollingInterest" xlink:label="BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedLessNoncontrollingInterest" xlink:title="BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedLessNoncontrollingInterest" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract" xlink:to="BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedLessNoncontrollingInterest" xlink:title="definition: BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract to BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedLessNoncontrollingInterest" use="optional" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife" xlink:label="AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife" xlink:title="AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract" xlink:to="AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife" xlink:title="definition: BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract to AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife" use="optional" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxAssetsNoncurrent" xlink:label="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxAssetsNoncurrent" xlink:title="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxAssetsNoncurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract" xlink:to="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxAssetsNoncurrent" xlink:title="definition: BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract to BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxAssetsNoncurrent" use="optional" order="8000.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsAndCurrentLiabilitiesNet" xlink:label="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsAndCurrentLiabilitiesNet" xlink:title="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsAndCurrentLiabilitiesNet" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract" xlink:to="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsAndCurrentLiabilitiesNet" xlink:title="definition: BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract to BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsAndCurrentLiabilitiesNet" use="optional" order="8001.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDebtAndOtherLiabilities" xlink:label="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDebtAndOtherLiabilities" xlink:title="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDebtAndOtherLiabilities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract" xlink:to="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDebtAndOtherLiabilities" xlink:title="definition: BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract to BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDebtAndOtherLiabilities" use="optional" order="8002.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_BusinessCombinationContingentConsiderationAsset" xlink:label="BusinessCombinationContingentConsiderationAsset" xlink:title="BusinessCombinationContingentConsiderationAsset" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract" xlink:to="BusinessCombinationContingentConsiderationAsset" xlink:title="definition: BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract to BusinessCombinationContingentConsiderationAsset" use="optional" order="8003.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_BusinessCombinationAcquisitionOfLessThan100PercentNoncontrollingInterestFairValue" xlink:label="BusinessCombinationAcquisitionOfLessThan100PercentNoncontrollingInterestFairValue" xlink:title="BusinessCombinationAcquisitionOfLessThan100PercentNoncontrollingInterestFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract" xlink:to="BusinessCombinationAcquisitionOfLessThan100PercentNoncontrollingInterestFairValue" xlink:title="definition: BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNetAbstract to BusinessCombinationAcquisitionOfLessThan100PercentNoncontrollingInterestFairValue" use="optional" order="8004.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_BusinessCombinationAdditionalDisclosuresAbstract" xlink:label="BusinessCombinationAdditionalDisclosuresAbstract" xlink:title="BusinessCombinationAdditionalDisclosuresAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessCombinationAdditionalDisclosuresAbstract" xlink:title="definition: BusinessAcquisitionLineItems to BusinessCombinationAdditionalDisclosuresAbstract" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_BusinessCombinationProFormaInformationRevenueOfAcquireeSinceAcquisitionDateActual" xlink:label="BusinessCombinationProFormaInformationRevenueOfAcquireeSinceAcquisitionDateActual" xlink:title="BusinessCombinationProFormaInformationRevenueOfAcquireeSinceAcquisitionDateActual" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationAdditionalDisclosuresAbstract" xlink:to="BusinessCombinationProFormaInformationRevenueOfAcquireeSinceAcquisitionDateActual" xlink:title="definition: BusinessCombinationAdditionalDisclosuresAbstract to BusinessCombinationProFormaInformationRevenueOfAcquireeSinceAcquisitionDateActual" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_BusinessCombinationProFormaInformationEarningsOrLossOfAcquireeSinceAcquisitionDateActual" xlink:label="BusinessCombinationProFormaInformationEarningsOrLossOfAcquireeSinceAcquisitionDateActual" xlink:title="BusinessCombinationProFormaInformationEarningsOrLossOfAcquireeSinceAcquisitionDateActual" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationAdditionalDisclosuresAbstract" xlink:to="BusinessCombinationProFormaInformationEarningsOrLossOfAcquireeSinceAcquisitionDateActual" xlink:title="definition: BusinessCombinationAdditionalDisclosuresAbstract to BusinessCombinationProFormaInformationEarningsOrLossOfAcquireeSinceAcquisitionDateActual" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_BusinessAcquisitionProFormaInformationAbstract" xlink:label="BusinessAcquisitionProFormaInformationAbstract" xlink:title="BusinessAcquisitionProFormaInformationAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessAcquisitionProFormaInformationAbstract" xlink:title="definition: BusinessAcquisitionLineItems to BusinessAcquisitionProFormaInformationAbstract" use="optional" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_BusinessAcquisitionsProFormaRevenue" xlink:label="BusinessAcquisitionsProFormaRevenue" xlink:title="BusinessAcquisitionsProFormaRevenue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionProFormaInformationAbstract" xlink:to="BusinessAcquisitionsProFormaRevenue" xlink:title="definition: BusinessAcquisitionProFormaInformationAbstract to BusinessAcquisitionsProFormaRevenue" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_BusinessAcquisitionsProFormaNetIncomeLoss" xlink:label="BusinessAcquisitionsProFormaNetIncomeLoss" xlink:title="BusinessAcquisitionsProFormaNetIncomeLoss" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionProFormaInformationAbstract" xlink:to="BusinessAcquisitionsProFormaNetIncomeLoss" xlink:title="definition: BusinessAcquisitionProFormaInformationAbstract to BusinessAcquisitionsProFormaNetIncomeLoss" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_BusinessAcquisitionAdditionalInformationAbstract" xlink:label="BusinessAcquisitionAdditionalInformationAbstract" xlink:title="BusinessAcquisitionAdditionalInformationAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessAcquisitionAdditionalInformationAbstract" xlink:title="definition: BusinessAcquisitionLineItems to BusinessAcquisitionAdditionalInformationAbstract" use="optional" order="8001.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfOperatingIncomeLoss" xlink:label="BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfOperatingIncomeLoss" xlink:title="BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfOperatingIncomeLoss" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionAdditionalInformationAbstract" xlink:to="BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfOperatingIncomeLoss" xlink:title="definition: BusinessAcquisitionAdditionalInformationAbstract to BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfOperatingIncomeLoss" use="optional" order="8001.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_BusinessCombinationContingentConsiderationLiabilityInterestAccretion" xlink:label="BusinessCombinationContingentConsiderationLiabilityInterestAccretion" xlink:title="BusinessCombinationContingentConsiderationLiabilityInterestAccretion" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionAdditionalInformationAbstract" xlink:to="BusinessCombinationContingentConsiderationLiabilityInterestAccretion" xlink:title="definition: BusinessAcquisitionAdditionalInformationAbstract to BusinessCombinationContingentConsiderationLiabilityInterestAccretion" use="optional" order="8002.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_NumberOfBusinessesAcquiredAsAssetPurchases" xlink:label="NumberOfBusinessesAcquiredAsAssetPurchases" xlink:title="NumberOfBusinessesAcquiredAsAssetPurchases" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="NumberOfBusinessesAcquiredAsAssetPurchases" xlink:title="definition: BusinessAcquisitionLineItems to NumberOfBusinessesAcquiredAsAssetPurchases" use="optional" order="8002.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_NumberOfBusinessesAcquiredAsAssetPurchasesInFrance" xlink:label="NumberOfBusinessesAcquiredAsAssetPurchasesInFrance" xlink:title="NumberOfBusinessesAcquiredAsAssetPurchasesInFrance" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="NumberOfBusinessesAcquiredAsAssetPurchasesInFrance" xlink:title="definition: BusinessAcquisitionLineItems to NumberOfBusinessesAcquiredAsAssetPurchasesInFrance" order="8003.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_AcquisitionRelatedCostsAndFairValueAdjustmentsToInitialPurchasePriceAllocationAbstract" xlink:label="AcquisitionRelatedCostsAndFairValueAdjustmentsToInitialPurchasePriceAllocationAbstract" xlink:title="AcquisitionRelatedCostsAndFairValueAdjustmentsToInitialPurchasePriceAllocationAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="AcquisitionRelatedCostsAndFairValueAdjustmentsToInitialPurchasePriceAllocationAbstract" xlink:title="definition: BusinessAcquisitionLineItems to AcquisitionRelatedCostsAndFairValueAdjustmentsToInitialPurchasePriceAllocationAbstract" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_BusinessAcquisitionCostOfAcquiredEntityTransactionCosts" xlink:label="BusinessAcquisitionCostOfAcquiredEntityTransactionCosts" xlink:title="BusinessAcquisitionCostOfAcquiredEntityTransactionCosts" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AcquisitionRelatedCostsAndFairValueAdjustmentsToInitialPurchasePriceAllocationAbstract" xlink:to="BusinessAcquisitionCostOfAcquiredEntityTransactionCosts" xlink:title="definition: AcquisitionRelatedCostsAndFairValueAdjustmentsToInitialPurchasePriceAllocationAbstract to BusinessAcquisitionCostOfAcquiredEntityTransactionCosts" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1" xlink:label="BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1" xlink:title="BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AcquisitionRelatedCostsAndFairValueAdjustmentsToInitialPurchasePriceAllocationAbstract" xlink:to="BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1" xlink:title="definition: AcquisitionRelatedCostsAndFairValueAdjustmentsToInitialPurchasePriceAllocationAbstract to BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_AcquisitionRelatedCostsAndFairValueAdjustmentsToInitialPurchasePriceAllocation" xlink:label="AcquisitionRelatedCostsAndFairValueAdjustmentsToInitialPurchasePriceAllocation" xlink:title="AcquisitionRelatedCostsAndFairValueAdjustmentsToInitialPurchasePriceAllocation" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AcquisitionRelatedCostsAndFairValueAdjustmentsToInitialPurchasePriceAllocationAbstract" xlink:to="AcquisitionRelatedCostsAndFairValueAdjustmentsToInitialPurchasePriceAllocation" xlink:title="definition: AcquisitionRelatedCostsAndFairValueAdjustmentsToInitialPurchasePriceAllocationAbstract to AcquisitionRelatedCostsAndFairValueAdjustmentsToInitialPurchasePriceAllocation" order="3.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://www.mistrasgroup.com/role/DisclosureSubsequentEventDetails">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="BusinessAcquisitionAxis" xlink:title="BusinessAcquisitionAxis" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="BusinessAcquisitionAcquireeDomain" xlink:title="BusinessAcquisitionAcquireeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="BusinessAcquisitionAxis" xlink:to="BusinessAcquisitionAcquireeDomain" xlink:title="definition: BusinessAcquisitionAxis to BusinessAcquisitionAcquireeDomain" use="optional" order="8000.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember" xlink:label="SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember" xlink:title="SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionAcquireeDomain" xlink:to="SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember" xlink:title="definition: BusinessAcquisitionAcquireeDomain to SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember" use="optional" order="8000.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_SubsequentEventLineItems" xlink:label="SubsequentEventLineItems" xlink:title="SubsequentEventLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_SubsequentEventTable" xlink:label="SubsequentEventTable" xlink:title="SubsequentEventTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="SubsequentEventLineItems" xlink:to="SubsequentEventTable" xlink:title="definition: SubsequentEventLineItems to SubsequentEventTable" use="optional" order="1.0" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="SubsequentEventTypeAxis" xlink:title="SubsequentEventTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="SubsequentEventTable" xlink:to="SubsequentEventTypeAxis" xlink:title="definition: SubsequentEventTable to SubsequentEventTypeAxis" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="SubsequentEventTypeDomain" xlink:title="SubsequentEventTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="SubsequentEventTypeAxis" xlink:to="SubsequentEventTypeDomain" xlink:title="definition: SubsequentEventTypeAxis to SubsequentEventTypeDomain" use="optional" order="8000.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="SubsequentEventTypeDomain_2" xlink:title="SubsequentEventTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="SubsequentEventTypeAxis" xlink:to="SubsequentEventTypeDomain_2" xlink:title="definition: SubsequentEventTypeAxis to SubsequentEventTypeDomain" use="optional" order="8001.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_SubsequentEventMember" xlink:label="SubsequentEventMember" xlink:title="SubsequentEventMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsequentEventTypeDomain" xlink:to="SubsequentEventMember" xlink:title="definition: SubsequentEventTypeDomain to SubsequentEventMember" use="optional" order="8000.0" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="SubsequentEventTable" xlink:to="BusinessAcquisitionAxis" xlink:title="definition: SubsequentEventTable to BusinessAcquisitionAxis" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_NumberOfBusinessesAcquiredAsAssetPurchasesInCanada" xlink:label="NumberOfBusinessesAcquiredAsAssetPurchasesInCanada" xlink:title="NumberOfBusinessesAcquiredAsAssetPurchasesInCanada" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsequentEventLineItems" xlink:to="NumberOfBusinessesAcquiredAsAssetPurchasesInCanada" xlink:title="definition: SubsequentEventLineItems to NumberOfBusinessesAcquiredAsAssetPurchasesInCanada" use="optional" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_NumberOfYearsOfOperationWithinWhichAcquiredCompanyAchieveSpecificPerformanceMetricsAfterWhichSellersOfContingentConsiderationReceivePotentialPayment" xlink:label="NumberOfYearsOfOperationWithinWhichAcquiredCompanyAchieveSpecificPerformanceMetricsAfterWhichSellersOfContingentConsiderationReceivePotentialPayment" xlink:title="NumberOfYearsOfOperationWithinWhichAcquiredCompanyAchieveSpecificPerformanceMetricsAfterWhichSellersOfContingentConsiderationReceivePotentialPayment" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SubsequentEventLineItems" xlink:to="NumberOfYearsOfOperationWithinWhichAcquiredCompanyAchieveSpecificPerformanceMetricsAfterWhichSellersOfContingentConsiderationReceivePotentialPayment" xlink:title="definition: SubsequentEventLineItems to NumberOfYearsOfOperationWithinWhichAcquiredCompanyAchieveSpecificPerformanceMetricsAfterWhichSellersOfContingentConsiderationReceivePotentialPayment" use="optional" order="5.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://www.mistrasgroup.com/role/DisclosurePropertyPlantAndEquipmentNetDetails">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_RangeAxis" xlink:label="RangeAxis" xlink:title="RangeAxis" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_RangeMember" xlink:label="RangeMember" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RangeAxis" xlink:to="RangeMember" xlink:title="definition: RangeAxis to RangeMember" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_MinimumMember" xlink:label="MinimumMember" xlink:title="MinimumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MinimumMember" xlink:title="definition: RangeMember to MinimumMember" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_MaximumMember" xlink:label="MaximumMember" xlink:title="MaximumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MaximumMember" xlink:title="definition: RangeMember to MaximumMember" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems" xlink:label="PropertyPlantAndEquipmentLineItems" xlink:title="PropertyPlantAndEquipmentLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:label="ScheduleOfPropertyPlantAndEquipmentTable" xlink:title="ScheduleOfPropertyPlantAndEquipmentTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="ScheduleOfPropertyPlantAndEquipmentTable" xlink:title="definition: PropertyPlantAndEquipmentLineItems to ScheduleOfPropertyPlantAndEquipmentTable" use="optional" order="1.0" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:label="PropertyPlantAndEquipmentByTypeAxis" xlink:title="PropertyPlantAndEquipmentByTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfPropertyPlantAndEquipmentTable" xlink:to="PropertyPlantAndEquipmentByTypeAxis" xlink:title="definition: ScheduleOfPropertyPlantAndEquipmentTable to PropertyPlantAndEquipmentByTypeAxis" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="PropertyPlantAndEquipmentTypeDomain" xlink:title="PropertyPlantAndEquipmentTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="PropertyPlantAndEquipmentByTypeAxis" xlink:to="PropertyPlantAndEquipmentTypeDomain" xlink:title="definition: PropertyPlantAndEquipmentByTypeAxis to PropertyPlantAndEquipmentTypeDomain" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="PropertyPlantAndEquipmentTypeDomain_2" xlink:title="PropertyPlantAndEquipmentTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="PropertyPlantAndEquipmentByTypeAxis" xlink:to="PropertyPlantAndEquipmentTypeDomain_2" xlink:title="definition: PropertyPlantAndEquipmentByTypeAxis to PropertyPlantAndEquipmentTypeDomain" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_LandMember" xlink:label="LandMember" xlink:title="LandMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentTypeDomain" xlink:to="LandMember" xlink:title="definition: PropertyPlantAndEquipmentTypeDomain to LandMember" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_BuildingAndBuildingImprovementsMember" xlink:label="BuildingAndBuildingImprovementsMember" xlink:title="BuildingAndBuildingImprovementsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentTypeDomain" xlink:to="BuildingAndBuildingImprovementsMember" xlink:title="definition: PropertyPlantAndEquipmentTypeDomain to BuildingAndBuildingImprovementsMember" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_OfficeFurnitureAndEquipmentMember" xlink:label="OfficeFurnitureAndEquipmentMember" xlink:title="OfficeFurnitureAndEquipmentMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentTypeDomain" xlink:to="OfficeFurnitureAndEquipmentMember" xlink:title="definition: PropertyPlantAndEquipmentTypeDomain to OfficeFurnitureAndEquipmentMember" use="optional" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_MachineryAndEquipmentMember" xlink:label="MachineryAndEquipmentMember" xlink:title="MachineryAndEquipmentMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentTypeDomain" xlink:to="MachineryAndEquipmentMember" xlink:title="definition: PropertyPlantAndEquipmentTypeDomain to MachineryAndEquipmentMember" use="optional" order="4.0" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfPropertyPlantAndEquipmentTable" xlink:to="RangeAxis" xlink:title="definition: ScheduleOfPropertyPlantAndEquipmentTable to RangeAxis" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:label="PropertyPlantAndEquipmentUsefulLife" xlink:title="PropertyPlantAndEquipmentUsefulLife" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="PropertyPlantAndEquipmentUsefulLife" xlink:title="definition: PropertyPlantAndEquipmentLineItems to PropertyPlantAndEquipmentUsefulLife" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross" xlink:label="PropertyPlantAndEquipmentGross" xlink:title="PropertyPlantAndEquipmentGross" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="PropertyPlantAndEquipmentGross" xlink:title="definition: PropertyPlantAndEquipmentLineItems to PropertyPlantAndEquipmentGross" use="optional" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:label="AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:title="AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:title="definition: PropertyPlantAndEquipmentLineItems to AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" use="optional" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="PropertyPlantAndEquipmentNet" xlink:title="PropertyPlantAndEquipmentNet" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="PropertyPlantAndEquipmentNet" xlink:title="definition: PropertyPlantAndEquipmentLineItems to PropertyPlantAndEquipmentNet" use="optional" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_Depreciation" xlink:label="Depreciation" xlink:title="Depreciation" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="Depreciation" xlink:title="definition: PropertyPlantAndEquipmentLineItems to Depreciation" use="optional" order="6.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://www.mistrasgroup.com/role/DisclosureLongTermDebtDetails">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_RangeAxis" xlink:label="RangeAxis" xlink:title="RangeAxis" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_RangeMember" xlink:label="RangeMember" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RangeAxis" xlink:to="RangeMember" xlink:title="definition: RangeAxis to RangeMember" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_MinimumMember" xlink:label="MinimumMember" xlink:title="MinimumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MinimumMember" xlink:title="definition: RangeMember to MinimumMember" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_MaximumMember" xlink:label="MaximumMember" xlink:title="MaximumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MaximumMember" xlink:title="definition: RangeMember to MaximumMember" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="DebtInstrumentLineItems" xlink:title="DebtInstrumentLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:label="DebtInstrumentTable" xlink:title="DebtInstrumentTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentTable" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentTable" use="optional" order="1.0" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="LongtermDebtTypeAxis" xlink:title="LongtermDebtTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DebtInstrumentTable" xlink:to="LongtermDebtTypeAxis" xlink:title="definition: DebtInstrumentTable to LongtermDebtTypeAxis" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="LongtermDebtTypeDomain" xlink:title="LongtermDebtTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="LongtermDebtTypeAxis" xlink:to="LongtermDebtTypeDomain" xlink:title="definition: LongtermDebtTypeAxis to LongtermDebtTypeDomain" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="LongtermDebtTypeDomain_2" xlink:title="LongtermDebtTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="LongtermDebtTypeAxis" xlink:to="LongtermDebtTypeDomain_2" xlink:title="definition: LongtermDebtTypeAxis to LongtermDebtTypeDomain" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_RevolvingCreditFacilityMember" xlink:label="RevolvingCreditFacilityMember" xlink:title="RevolvingCreditFacilityMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LongtermDebtTypeDomain" xlink:to="RevolvingCreditFacilityMember" xlink:title="definition: LongtermDebtTypeDomain to RevolvingCreditFacilityMember" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_NotesPayableOtherPayablesMember" xlink:label="NotesPayableOtherPayablesMember" xlink:title="NotesPayableOtherPayablesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LongtermDebtTypeDomain" xlink:to="NotesPayableOtherPayablesMember" xlink:title="definition: LongtermDebtTypeDomain to NotesPayableOtherPayablesMember" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_OtherLongTermDebtMember" xlink:label="OtherLongTermDebtMember" xlink:title="OtherLongTermDebtMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LongtermDebtTypeDomain" xlink:to="OtherLongTermDebtMember" xlink:title="definition: LongtermDebtTypeDomain to OtherLongTermDebtMember" use="optional" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_VariableRateAxis" xlink:label="VariableRateAxis" xlink:title="VariableRateAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DebtInstrumentTable" xlink:to="VariableRateAxis" xlink:title="definition: DebtInstrumentTable to VariableRateAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_VariableRateDomain" xlink:label="VariableRateDomain" xlink:title="VariableRateDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="VariableRateAxis" xlink:to="VariableRateDomain" xlink:title="definition: VariableRateAxis to VariableRateDomain" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_VariableRateDomain" xlink:label="VariableRateDomain_2" xlink:title="VariableRateDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="VariableRateAxis" xlink:to="VariableRateDomain_2" xlink:title="definition: VariableRateAxis to VariableRateDomain" use="optional" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_LondonInterbankOfferedRateLIBORMember" xlink:label="LondonInterbankOfferedRateLIBORMember" xlink:title="LondonInterbankOfferedRateLIBORMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="VariableRateDomain" xlink:to="LondonInterbankOfferedRateLIBORMember" xlink:title="definition: VariableRateDomain to LondonInterbankOfferedRateLIBORMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_BaseRateMember" xlink:label="BaseRateMember" xlink:title="BaseRateMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="VariableRateDomain" xlink:to="BaseRateMember" xlink:title="definition: VariableRateDomain to BaseRateMember" use="optional" order="2.0" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DebtInstrumentTable" xlink:to="RangeAxis" xlink:title="definition: DebtInstrumentTable to RangeAxis" use="optional" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_LongTermDebt" xlink:label="LongTermDebt" xlink:title="LongTermDebt" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LongTermDebt" xlink:title="definition: DebtInstrumentLineItems to LongTermDebt" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_LongTermDebtCurrent" xlink:label="LongTermDebtCurrent" xlink:title="LongTermDebtCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LongTermDebtCurrent" xlink:title="definition: DebtInstrumentLineItems to LongTermDebtCurrent" use="optional" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_LongTermDebtNoncurrent" xlink:label="LongTermDebtNoncurrent" xlink:title="LongTermDebtNoncurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LongTermDebtNoncurrent" xlink:title="definition: DebtInstrumentLineItems to LongTermDebtNoncurrent" use="optional" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity" xlink:label="LineOfCreditFacilityCurrentBorrowingCapacity" xlink:title="LineOfCreditFacilityCurrentBorrowingCapacity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LineOfCreditFacilityCurrentBorrowingCapacity" xlink:title="definition: DebtInstrumentLineItems to LineOfCreditFacilityCurrentBorrowingCapacity" use="optional" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:label="LineOfCreditFacilityMaximumBorrowingCapacity" xlink:title="LineOfCreditFacilityMaximumBorrowingCapacity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LineOfCreditFacilityMaximumBorrowingCapacity" xlink:title="definition: DebtInstrumentLineItems to LineOfCreditFacilityMaximumBorrowingCapacity" use="optional" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_LineOfCreditFacilityMaximumBorrowingCapacityInNonUSCurrencies" xlink:label="LineOfCreditFacilityMaximumBorrowingCapacityInNonUSCurrencies" xlink:title="LineOfCreditFacilityMaximumBorrowingCapacityInNonUSCurrencies" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LineOfCreditFacilityMaximumBorrowingCapacityInNonUSCurrencies" xlink:title="definition: DebtInstrumentLineItems to LineOfCreditFacilityMaximumBorrowingCapacityInNonUSCurrencies" use="optional" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_LineOfCreditFacilityMaximumBorrowingCapacityAvailableForIssuanceOfLettersOfCredit" xlink:label="LineOfCreditFacilityMaximumBorrowingCapacityAvailableForIssuanceOfLettersOfCredit" xlink:title="LineOfCreditFacilityMaximumBorrowingCapacityAvailableForIssuanceOfLettersOfCredit" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LineOfCreditFacilityMaximumBorrowingCapacityAvailableForIssuanceOfLettersOfCredit" xlink:title="definition: DebtInstrumentLineItems to LineOfCreditFacilityMaximumBorrowingCapacityAvailableForIssuanceOfLettersOfCredit" use="optional" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_LineOfCreditFacilityAmountOutstanding" xlink:label="LineOfCreditFacilityAmountOutstanding" xlink:title="LineOfCreditFacilityAmountOutstanding" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LineOfCreditFacilityAmountOutstanding" xlink:title="definition: DebtInstrumentLineItems to LineOfCreditFacilityAmountOutstanding" use="optional" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_LettersOfCreditOutstandingAmount" xlink:label="LettersOfCreditOutstandingAmount" xlink:title="LettersOfCreditOutstandingAmount" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LettersOfCreditOutstandingAmount" xlink:title="definition: DebtInstrumentLineItems to LettersOfCreditOutstandingAmount" use="optional" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_DebtInstrumentDescriptionOfVariableRateBasis" xlink:label="DebtInstrumentDescriptionOfVariableRateBasis" xlink:title="DebtInstrumentDescriptionOfVariableRateBasis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentDescriptionOfVariableRateBasis" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentDescriptionOfVariableRateBasis" use="optional" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" xlink:label="DebtInstrumentBasisSpreadOnVariableRate1" xlink:title="DebtInstrumentBasisSpreadOnVariableRate1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentBasisSpreadOnVariableRate1" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentBasisSpreadOnVariableRate1" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_DebtInstrumentNumberOfFiscalQuartersUsedForCalculationOfFundedDebtLeverageRatio" xlink:label="DebtInstrumentNumberOfFiscalQuartersUsedForCalculationOfFundedDebtLeverageRatio" xlink:title="DebtInstrumentNumberOfFiscalQuartersUsedForCalculationOfFundedDebtLeverageRatio" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentNumberOfFiscalQuartersUsedForCalculationOfFundedDebtLeverageRatio" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentNumberOfFiscalQuartersUsedForCalculationOfFundedDebtLeverageRatio" use="optional" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_DebtInstrumentCovenantFundedLeverageRatioConsideredForLowerInterestRateMargin" xlink:label="DebtInstrumentCovenantFundedLeverageRatioConsideredForLowerInterestRateMargin" xlink:title="DebtInstrumentCovenantFundedLeverageRatioConsideredForLowerInterestRateMargin" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentCovenantFundedLeverageRatioConsideredForLowerInterestRateMargin" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentCovenantFundedLeverageRatioConsideredForLowerInterestRateMargin" use="optional" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_DebtInstrumentCovenantFundedLeverageRatioConsideredForMaximumInterestRateMargin" xlink:label="DebtInstrumentCovenantFundedLeverageRatioConsideredForMaximumInterestRateMargin" xlink:title="DebtInstrumentCovenantFundedLeverageRatioConsideredForMaximumInterestRateMargin" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentCovenantFundedLeverageRatioConsideredForMaximumInterestRateMargin" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentCovenantFundedLeverageRatioConsideredForMaximumInterestRateMargin" use="optional" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_DebtInstrumentAdditionalInterestRateDueToFundedDebtLeverageRatioExceedingSpecifiedThreshold" xlink:label="DebtInstrumentAdditionalInterestRateDueToFundedDebtLeverageRatioExceedingSpecifiedThreshold" xlink:title="DebtInstrumentAdditionalInterestRateDueToFundedDebtLeverageRatioExceedingSpecifiedThreshold" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentAdditionalInterestRateDueToFundedDebtLeverageRatioExceedingSpecifiedThreshold" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentAdditionalInterestRateDueToFundedDebtLeverageRatioExceedingSpecifiedThreshold" use="optional" order="16.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_DebtInstrumentCovenantFundedDebtLeverageRatioForAdditionalInterestPayment" xlink:label="DebtInstrumentCovenantFundedDebtLeverageRatioForAdditionalInterestPayment" xlink:title="DebtInstrumentCovenantFundedDebtLeverageRatioForAdditionalInterestPayment" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentCovenantFundedDebtLeverageRatioForAdditionalInterestPayment" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentCovenantFundedDebtLeverageRatioForAdditionalInterestPayment" use="optional" order="17.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_DebtInstrumentCovenantFundedDebtLeverageRatio" xlink:label="DebtInstrumentCovenantFundedDebtLeverageRatio" xlink:title="DebtInstrumentCovenantFundedDebtLeverageRatio" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentCovenantFundedDebtLeverageRatio" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentCovenantFundedDebtLeverageRatio" use="optional" order="18.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_DebtInstrumentCovenantInterestCoverageRatio" xlink:label="DebtInstrumentCovenantInterestCoverageRatio" xlink:title="DebtInstrumentCovenantInterestCoverageRatio" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentCovenantInterestCoverageRatio" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentCovenantInterestCoverageRatio" use="optional" order="19.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_DebtInstrumentPrecedingPeriodUsedForCalculationOfInterestCoverageRatio" xlink:label="DebtInstrumentPrecedingPeriodUsedForCalculationOfInterestCoverageRatio" xlink:title="DebtInstrumentPrecedingPeriodUsedForCalculationOfInterestCoverageRatio" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentPrecedingPeriodUsedForCalculationOfInterestCoverageRatio" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentPrecedingPeriodUsedForCalculationOfInterestCoverageRatio" use="optional" order="20.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_UnamortizedDebtIssuanceExpense" xlink:label="UnamortizedDebtIssuanceExpense" xlink:title="UnamortizedDebtIssuanceExpense" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="UnamortizedDebtIssuanceExpense" xlink:title="definition: DebtInstrumentLineItems to UnamortizedDebtIssuanceExpense" use="optional" order="21.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_WriteOffOfDeferredDebtIssuanceCost" xlink:label="WriteOffOfDeferredDebtIssuanceCost" xlink:title="WriteOffOfDeferredDebtIssuanceCost" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="WriteOffOfDeferredDebtIssuanceCost" xlink:title="definition: DebtInstrumentLineItems to WriteOffOfDeferredDebtIssuanceCost" use="optional" order="22.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:label="GainsLossesOnExtinguishmentOfDebt" xlink:title="GainsLossesOnExtinguishmentOfDebt" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="GainsLossesOnExtinguishmentOfDebt" xlink:title="definition: DebtInstrumentLineItems to GainsLossesOnExtinguishmentOfDebt" use="optional" order="23.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_DebtInstrumentTerm" xlink:label="DebtInstrumentTerm" xlink:title="DebtInstrumentTerm" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentTerm" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentTerm" order="24.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum" xlink:label="DebtInstrumentInterestRateStatedPercentageRateRangeMinimum" xlink:title="DebtInstrumentInterestRateStatedPercentageRateRangeMinimum" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentInterestRateStatedPercentageRateRangeMinimum" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentInterestRateStatedPercentageRateRangeMinimum" use="optional" order="25.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum" xlink:label="DebtInstrumentInterestRateStatedPercentageRateRangeMaximum" xlink:title="DebtInstrumentInterestRateStatedPercentageRateRangeMaximum" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentInterestRateStatedPercentageRateRangeMaximum" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentInterestRateStatedPercentageRateRangeMaximum" use="optional" order="26.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_DebtInstrumentMarketInterestRate" xlink:label="DebtInstrumentMarketInterestRate" xlink:title="DebtInstrumentMarketInterestRate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentMarketInterestRate" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentMarketInterestRate" use="optional" order="27.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_DebtInstrumentUnamortizedDiscount" xlink:label="DebtInstrumentUnamortizedDiscount" xlink:title="DebtInstrumentUnamortizedDiscount" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentUnamortizedDiscount" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentUnamortizedDiscount" use="optional" order="28.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_DebtInstrumentImputedInterestRate" xlink:label="DebtInstrumentImputedInterestRate" xlink:title="DebtInstrumentImputedInterestRate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentImputedInterestRate" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentImputedInterestRate" use="optional" order="8000.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_PeriodForPaymentUnderNoncompeteAgreements" xlink:label="PeriodForPaymentUnderNoncompeteAgreements" xlink:title="PeriodForPaymentUnderNoncompeteAgreements" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="PeriodForPaymentUnderNoncompeteAgreements" xlink:title="definition: DebtInstrumentLineItems to PeriodForPaymentUnderNoncompeteAgreements" use="optional" order="8001.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://www.mistrasgroup.com/role/DisclosureIntangibleAssetsDetails">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_RangeAxis" xlink:label="RangeAxis" xlink:title="RangeAxis" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_RangeMember" xlink:label="RangeMember" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RangeAxis" xlink:to="RangeMember" xlink:title="definition: RangeAxis to RangeMember" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_MinimumMember" xlink:label="MinimumMember" xlink:title="MinimumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MinimumMember" xlink:title="definition: RangeMember to MinimumMember" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_MaximumMember" xlink:label="MaximumMember" xlink:title="MaximumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MaximumMember" xlink:title="definition: RangeMember to MaximumMember" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:label="FiniteLivedIntangibleAssetsLineItems" xlink:title="FiniteLivedIntangibleAssetsLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:label="ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:title="ScheduleOfFiniteLivedIntangibleAssetsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="FiniteLivedIntangibleAssetsLineItems" xlink:to="ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:title="definition: FiniteLivedIntangibleAssetsLineItems to ScheduleOfFiniteLivedIntangibleAssetsTable" order="1.0" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:label="FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:title="FiniteLivedIntangibleAssetsByMajorClassAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:to="FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:title="definition: ScheduleOfFiniteLivedIntangibleAssetsTable to FiniteLivedIntangibleAssetsByMajorClassAxis" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:title="FiniteLivedIntangibleAssetsMajorClassNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:title="definition: FiniteLivedIntangibleAssetsByMajorClassAxis to FiniteLivedIntangibleAssetsMajorClassNameDomain" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="FiniteLivedIntangibleAssetsMajorClassNameDomain_2" xlink:title="FiniteLivedIntangibleAssetsMajorClassNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="FiniteLivedIntangibleAssetsMajorClassNameDomain_2" xlink:title="definition: FiniteLivedIntangibleAssetsByMajorClassAxis to FiniteLivedIntangibleAssetsMajorClassNameDomain" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_CustomerRelationshipsMember" xlink:label="CustomerRelationshipsMember" xlink:title="CustomerRelationshipsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="CustomerRelationshipsMember" xlink:title="definition: FiniteLivedIntangibleAssetsMajorClassNameDomain to CustomerRelationshipsMember" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ComputerSoftwareIntangibleAssetMember" xlink:label="ComputerSoftwareIntangibleAssetMember" xlink:title="ComputerSoftwareIntangibleAssetMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="ComputerSoftwareIntangibleAssetMember" xlink:title="definition: FiniteLivedIntangibleAssetsMajorClassNameDomain to ComputerSoftwareIntangibleAssetMember" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_NoncompeteAgreementsMember" xlink:label="NoncompeteAgreementsMember" xlink:title="NoncompeteAgreementsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="NoncompeteAgreementsMember" xlink:title="definition: FiniteLivedIntangibleAssetsMajorClassNameDomain to NoncompeteAgreementsMember" use="optional" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_OtherIntangibleAssetsMember" xlink:label="OtherIntangibleAssetsMember" xlink:title="OtherIntangibleAssetsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="OtherIntangibleAssetsMember" xlink:title="definition: FiniteLivedIntangibleAssetsMajorClassNameDomain to OtherIntangibleAssetsMember" use="optional" order="4.0" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:to="RangeAxis" xlink:title="definition: ScheduleOfFiniteLivedIntangibleAssetsTable to RangeAxis" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife" xlink:label="FiniteLivedIntangibleAssetUsefulLife" xlink:title="FiniteLivedIntangibleAssetUsefulLife" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsLineItems" xlink:to="FiniteLivedIntangibleAssetUsefulLife" xlink:title="definition: FiniteLivedIntangibleAssetsLineItems to FiniteLivedIntangibleAssetUsefulLife" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsGross" xlink:label="FiniteLivedIntangibleAssetsGross" xlink:title="FiniteLivedIntangibleAssetsGross" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsLineItems" xlink:to="FiniteLivedIntangibleAssetsGross" xlink:title="definition: FiniteLivedIntangibleAssetsLineItems to FiniteLivedIntangibleAssetsGross" use="optional" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:label="FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:title="FiniteLivedIntangibleAssetsAccumulatedAmortization" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsLineItems" xlink:to="FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:title="definition: FiniteLivedIntangibleAssetsLineItems to FiniteLivedIntangibleAssetsAccumulatedAmortization" use="optional" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:label="IntangibleAssetsNetExcludingGoodwill" xlink:title="IntangibleAssetsNetExcludingGoodwill" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsLineItems" xlink:to="IntangibleAssetsNetExcludingGoodwill" xlink:title="definition: FiniteLivedIntangibleAssetsLineItems to IntangibleAssetsNetExcludingGoodwill" use="optional" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_AmortizationOfIntangibleAssets" xlink:label="AmortizationOfIntangibleAssets" xlink:title="AmortizationOfIntangibleAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsLineItems" xlink:to="AmortizationOfIntangibleAssets" xlink:title="definition: FiniteLivedIntangibleAssetsLineItems to AmortizationOfIntangibleAssets" use="optional" order="6.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://www.mistrasgroup.com/role/DisclosureObligationsUnderCapitalLeasesDetails">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_RangeAxis" xlink:label="RangeAxis" xlink:title="RangeAxis" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_RangeMember" xlink:label="RangeMember" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RangeAxis" xlink:to="RangeMember" xlink:title="definition: RangeAxis to RangeMember" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_MinimumMember" xlink:label="MinimumMember" xlink:title="MinimumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MinimumMember" xlink:title="definition: RangeMember to MinimumMember" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_MaximumMember" xlink:label="MaximumMember" xlink:title="MaximumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MaximumMember" xlink:title="definition: RangeMember to MaximumMember" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_CapitalLeasedAssetsLineItems" xlink:label="CapitalLeasedAssetsLineItems" xlink:title="CapitalLeasedAssetsLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ScheduleOfCapitalLeasedAsssetsTable" xlink:label="ScheduleOfCapitalLeasedAsssetsTable" xlink:title="ScheduleOfCapitalLeasedAsssetsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="CapitalLeasedAssetsLineItems" xlink:to="ScheduleOfCapitalLeasedAsssetsTable" xlink:title="definition: CapitalLeasedAssetsLineItems to ScheduleOfCapitalLeasedAsssetsTable" use="optional" order="1.0" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfCapitalLeasedAsssetsTable" xlink:to="RangeAxis" xlink:title="definition: ScheduleOfCapitalLeasedAsssetsTable to RangeAxis" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_CapitalLeaseObligationsRequiredMonthlyPayments" xlink:label="CapitalLeaseObligationsRequiredMonthlyPayments" xlink:title="CapitalLeaseObligationsRequiredMonthlyPayments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CapitalLeasedAssetsLineItems" xlink:to="CapitalLeaseObligationsRequiredMonthlyPayments" xlink:title="definition: CapitalLeasedAssetsLineItems to CapitalLeaseObligationsRequiredMonthlyPayments" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_CapitalLeaseObligationsEffectiveInterestRate" xlink:label="CapitalLeaseObligationsEffectiveInterestRate" xlink:title="CapitalLeaseObligationsEffectiveInterestRate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CapitalLeasedAssetsLineItems" xlink:to="CapitalLeaseObligationsEffectiveInterestRate" xlink:title="definition: CapitalLeasedAssetsLineItems to CapitalLeaseObligationsEffectiveInterestRate" use="optional" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_CapitalLeasesBalanceSheetAssetsByMajorClassNet" xlink:label="CapitalLeasesBalanceSheetAssetsByMajorClassNet" xlink:title="CapitalLeasesBalanceSheetAssetsByMajorClassNet" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CapitalLeasedAssetsLineItems" xlink:to="CapitalLeasesBalanceSheetAssetsByMajorClassNet" xlink:title="definition: CapitalLeasedAssetsLineItems to CapitalLeasesBalanceSheetAssetsByMajorClassNet" use="optional" order="4.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://www.mistrasgroup.com/role/DisclosureEmployeeBenefitPlansDetails">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_RangeAxis" xlink:label="RangeAxis" xlink:title="RangeAxis" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_RangeMember" xlink:label="RangeMember" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RangeAxis" xlink:to="RangeMember" xlink:title="definition: RangeAxis to RangeMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_RangeMember" xlink:label="RangeMember_2" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RangeAxis" xlink:to="RangeMember_2" xlink:title="definition: RangeAxis to RangeMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_MaximumMember" xlink:label="MaximumMember" xlink:title="MaximumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MaximumMember" xlink:title="definition: RangeMember to MaximumMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_DefinedContributionPlanLineItems" xlink:label="DefinedContributionPlanLineItems" xlink:title="DefinedContributionPlanLineItems" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_DefinedContributionPlanTable" xlink:label="DefinedContributionPlanTable" xlink:title="DefinedContributionPlanTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DefinedContributionPlanLineItems" xlink:to="DefinedContributionPlanTable" xlink:title="definition: DefinedContributionPlanLineItems to DefinedContributionPlanTable" order="1.0" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DefinedContributionPlanTable" xlink:to="RangeAxis" xlink:title="definition: DefinedContributionPlanTable to RangeAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent" xlink:label="DefinedContributionPlanEmployerMatchingContributionPercent" xlink:title="DefinedContributionPlanEmployerMatchingContributionPercent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefinedContributionPlanLineItems" xlink:to="DefinedContributionPlanEmployerMatchingContributionPercent" xlink:title="definition: DefinedContributionPlanLineItems to DefinedContributionPlanEmployerMatchingContributionPercent" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_MultiemployerPlansAbstract" xlink:label="MultiemployerPlansAbstract" xlink:title="MultiemployerPlansAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefinedContributionPlanLineItems" xlink:to="MultiemployerPlansAbstract" xlink:title="definition: DefinedContributionPlanLineItems to MultiemployerPlansAbstract" use="optional" order="8000.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://www.mistrasgroup.com/role/DisclosureSummaryOfSignificantAccountingPoliciesDetails">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_RangeAxis" xlink:label="RangeAxis" xlink:title="RangeAxis" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_RangeMember" xlink:label="RangeMember" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RangeAxis" xlink:to="RangeMember" xlink:title="definition: RangeAxis to RangeMember" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_MaximumMember" xlink:label="MaximumMember" xlink:title="MaximumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MaximumMember" xlink:title="definition: RangeMember to MaximumMember" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:label="FiniteLivedIntangibleAssetsLineItems" xlink:title="FiniteLivedIntangibleAssetsLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:label="ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:title="ScheduleOfFiniteLivedIntangibleAssetsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="FiniteLivedIntangibleAssetsLineItems" xlink:to="ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:title="definition: FiniteLivedIntangibleAssetsLineItems to ScheduleOfFiniteLivedIntangibleAssetsTable" order="1.0" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:label="FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:title="FiniteLivedIntangibleAssetsByMajorClassAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:to="FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:title="definition: ScheduleOfFiniteLivedIntangibleAssetsTable to FiniteLivedIntangibleAssetsByMajorClassAxis" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:title="FiniteLivedIntangibleAssetsMajorClassNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:title="definition: FiniteLivedIntangibleAssetsByMajorClassAxis to FiniteLivedIntangibleAssetsMajorClassNameDomain" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ComputerSoftwareIntangibleAssetMember" xlink:label="ComputerSoftwareIntangibleAssetMember" xlink:title="ComputerSoftwareIntangibleAssetMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="ComputerSoftwareIntangibleAssetMember" xlink:title="definition: FiniteLivedIntangibleAssetsMajorClassNameDomain to ComputerSoftwareIntangibleAssetMember" use="optional" order="1.0" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:to="RangeAxis" xlink:title="definition: ScheduleOfFiniteLivedIntangibleAssetsTable to RangeAxis" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife" xlink:label="FiniteLivedIntangibleAssetUsefulLife" xlink:title="FiniteLivedIntangibleAssetUsefulLife" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsLineItems" xlink:to="FiniteLivedIntangibleAssetUsefulLife" xlink:title="definition: FiniteLivedIntangibleAssetsLineItems to FiniteLivedIntangibleAssetUsefulLife" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ForeignCurrencyTranslationAbstract" xlink:label="ForeignCurrencyTranslationAbstract" xlink:title="ForeignCurrencyTranslationAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsLineItems" xlink:to="ForeignCurrencyTranslationAbstract" xlink:title="definition: FiniteLivedIntangibleAssetsLineItems to ForeignCurrencyTranslationAbstract" use="optional" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ForeignCurrencyTransactionGainLossBeforeTax" xlink:label="ForeignCurrencyTransactionGainLossBeforeTax" xlink:title="ForeignCurrencyTransactionGainLossBeforeTax" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ForeignCurrencyTranslationAbstract" xlink:to="ForeignCurrencyTransactionGainLossBeforeTax" xlink:title="definition: ForeignCurrencyTranslationAbstract to ForeignCurrencyTransactionGainLossBeforeTax" use="optional" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://www.mistrasgroup.com/role/DisclosureSegmentDisclosureDetails">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="StatementBusinessSegmentsAxis" xlink:title="StatementBusinessSegmentsAxis" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_SegmentDomain" xlink:label="SegmentDomain" xlink:title="SegmentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementBusinessSegmentsAxis" xlink:to="SegmentDomain" xlink:title="definition: StatementBusinessSegmentsAxis to SegmentDomain" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_InternationalMember" xlink:label="InternationalMember" xlink:title="InternationalMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentDomain" xlink:to="InternationalMember" xlink:title="definition: SegmentDomain to InternationalMember" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_ServicesMember" xlink:label="ServicesMember" xlink:title="ServicesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentDomain" xlink:to="ServicesMember" xlink:title="definition: SegmentDomain to ServicesMember" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_ProductsAndSystemsMember" xlink:label="ProductsAndSystemsMember" xlink:title="ProductsAndSystemsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentDomain" xlink:to="ProductsAndSystemsMember" xlink:title="definition: SegmentDomain to ProductsAndSystemsMember" use="optional" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_SegmentReportingInformationLineItems" xlink:label="SegmentReportingInformationLineItems" xlink:title="SegmentReportingInformationLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:label="ScheduleOfSegmentReportingInformationBySegmentTable" xlink:title="ScheduleOfSegmentReportingInformationBySegmentTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="SegmentReportingInformationLineItems" xlink:to="ScheduleOfSegmentReportingInformationBySegmentTable" xlink:title="definition: SegmentReportingInformationLineItems to ScheduleOfSegmentReportingInformationBySegmentTable" order="1.0" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ConsolidationItemsAxis" xlink:label="ConsolidationItemsAxis" xlink:title="ConsolidationItemsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfSegmentReportingInformationBySegmentTable" xlink:to="ConsolidationItemsAxis" xlink:title="definition: ScheduleOfSegmentReportingInformationBySegmentTable to ConsolidationItemsAxis" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="ConsolidationItemsDomain" xlink:title="ConsolidationItemsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ConsolidationItemsAxis" xlink:to="ConsolidationItemsDomain" xlink:title="definition: ConsolidationItemsAxis to ConsolidationItemsDomain" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="ConsolidationItemsDomain_2" xlink:title="ConsolidationItemsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ConsolidationItemsAxis" xlink:to="ConsolidationItemsDomain_2" xlink:title="definition: ConsolidationItemsAxis to ConsolidationItemsDomain" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_OperatingSegmentsMember" xlink:label="OperatingSegmentsMember" xlink:title="OperatingSegmentsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidationItemsDomain" xlink:to="OperatingSegmentsMember" xlink:title="definition: ConsolidationItemsDomain to OperatingSegmentsMember" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_IntersegmentEliminationMember" xlink:label="IntersegmentEliminationMember" xlink:title="IntersegmentEliminationMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConsolidationItemsDomain" xlink:to="IntersegmentEliminationMember" xlink:title="definition: ConsolidationItemsDomain to IntersegmentEliminationMember" use="optional" order="2.0" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfSegmentReportingInformationBySegmentTable" xlink:to="StatementBusinessSegmentsAxis" xlink:title="definition: ScheduleOfSegmentReportingInformationBySegmentTable to StatementBusinessSegmentsAxis" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_SalesRevenueNet" xlink:label="SalesRevenueNet" xlink:title="SalesRevenueNet" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentReportingInformationLineItems" xlink:to="SalesRevenueNet" xlink:title="definition: SegmentReportingInformationLineItems to SalesRevenueNet" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_GrossProfit" xlink:label="GrossProfit" xlink:title="GrossProfit" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentReportingInformationLineItems" xlink:to="GrossProfit" xlink:title="definition: SegmentReportingInformationLineItems to GrossProfit" use="optional" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="OperatingIncomeLoss" xlink:title="OperatingIncomeLoss" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentReportingInformationLineItems" xlink:to="OperatingIncomeLoss" xlink:title="definition: SegmentReportingInformationLineItems to OperatingIncomeLoss" use="optional" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_DepreciationDepletionAndAmortization" xlink:label="DepreciationDepletionAndAmortization" xlink:title="DepreciationDepletionAndAmortization" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentReportingInformationLineItems" xlink:to="DepreciationDepletionAndAmortization" xlink:title="definition: SegmentReportingInformationLineItems to DepreciationDepletionAndAmortization" use="optional" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:label="IntangibleAssetsNetExcludingGoodwill" xlink:title="IntangibleAssetsNetExcludingGoodwill" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentReportingInformationLineItems" xlink:to="IntangibleAssetsNetExcludingGoodwill" xlink:title="definition: SegmentReportingInformationLineItems to IntangibleAssetsNetExcludingGoodwill" use="optional" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_Assets" xlink:label="Assets" xlink:title="Assets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentReportingInformationLineItems" xlink:to="Assets" xlink:title="definition: SegmentReportingInformationLineItems to Assets" use="optional" order="8.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://www.mistrasgroup.com/role/DisclosureFairValueMeasurementsDetails">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:label="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:title="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:label="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:title="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:to="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems to FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" use="optional" order="1.0" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis" xlink:label="FairValueByMeasurementFrequencyAxis" xlink:title="FairValueByMeasurementFrequencyAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:to="FairValueByMeasurementFrequencyAxis" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable to FairValueByMeasurementFrequencyAxis" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="FairValueMeasurementFrequencyDomain" xlink:title="FairValueMeasurementFrequencyDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="FairValueByMeasurementFrequencyAxis" xlink:to="FairValueMeasurementFrequencyDomain" xlink:title="definition: FairValueByMeasurementFrequencyAxis to FairValueMeasurementFrequencyDomain" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="FairValueMeasurementFrequencyDomain_2" xlink:title="FairValueMeasurementFrequencyDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="FairValueByMeasurementFrequencyAxis" xlink:to="FairValueMeasurementFrequencyDomain_2" xlink:title="definition: FairValueByMeasurementFrequencyAxis to FairValueMeasurementFrequencyDomain" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember" xlink:label="FairValueMeasurementsRecurringMember" xlink:title="FairValueMeasurementsRecurringMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueMeasurementFrequencyDomain" xlink:to="FairValueMeasurementsRecurringMember" xlink:title="definition: FairValueMeasurementFrequencyDomain to FairValueMeasurementsRecurringMember" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="FairValueByFairValueHierarchyLevelAxis" xlink:title="FairValueByFairValueHierarchyLevelAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:to="FairValueByFairValueHierarchyLevelAxis" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable to FairValueByFairValueHierarchyLevelAxis" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="FairValueMeasurementsFairValueHierarchyDomain" xlink:title="FairValueMeasurementsFairValueHierarchyDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="FairValueByFairValueHierarchyLevelAxis" xlink:to="FairValueMeasurementsFairValueHierarchyDomain" xlink:title="definition: FairValueByFairValueHierarchyLevelAxis to FairValueMeasurementsFairValueHierarchyDomain" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="FairValueMeasurementsFairValueHierarchyDomain_2" xlink:title="FairValueMeasurementsFairValueHierarchyDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="FairValueByFairValueHierarchyLevelAxis" xlink:to="FairValueMeasurementsFairValueHierarchyDomain_2" xlink:title="definition: FairValueByFairValueHierarchyLevelAxis to FairValueMeasurementsFairValueHierarchyDomain" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="FairValueInputsLevel3Member" xlink:title="FairValueInputsLevel3Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueMeasurementsFairValueHierarchyDomain" xlink:to="FairValueInputsLevel3Member" xlink:title="definition: FairValueMeasurementsFairValueHierarchyDomain to FairValueInputsLevel3Member" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember" xlink:label="EstimateOfFairValueFairValueDisclosureMember" xlink:title="EstimateOfFairValueFairValueDisclosureMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueMeasurementsFairValueHierarchyDomain" xlink:to="EstimateOfFairValueFairValueDisclosureMember" xlink:title="definition: FairValueMeasurementsFairValueHierarchyDomain to EstimateOfFairValueFairValueDisclosureMember" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_FairValueInputsLevel1Member" xlink:label="FairValueInputsLevel1Member" xlink:title="FairValueInputsLevel1Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueMeasurementsFairValueHierarchyDomain" xlink:to="FairValueInputsLevel1Member" xlink:title="definition: FairValueMeasurementsFairValueHierarchyDomain to FairValueInputsLevel1Member" use="optional" order="8000.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_FairValueInputsLevel2Member" xlink:label="FairValueInputsLevel2Member" xlink:title="FairValueInputsLevel2Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueMeasurementsFairValueHierarchyDomain" xlink:to="FairValueInputsLevel2Member" xlink:title="definition: FairValueMeasurementsFairValueHierarchyDomain to FairValueInputsLevel2Member" use="optional" order="8001.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_LiabilitiesFairValueDisclosureAbstract" xlink:label="LiabilitiesFairValueDisclosureAbstract" xlink:title="LiabilitiesFairValueDisclosureAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:to="LiabilitiesFairValueDisclosureAbstract" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems to LiabilitiesFairValueDisclosureAbstract" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_BusinessCombinationContingentConsiderationLiability" xlink:label="BusinessCombinationContingentConsiderationLiability" xlink:title="BusinessCombinationContingentConsiderationLiability" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LiabilitiesFairValueDisclosureAbstract" xlink:to="BusinessCombinationContingentConsiderationLiability" xlink:title="definition: LiabilitiesFairValueDisclosureAbstract to BusinessCombinationContingentConsiderationLiability" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_LiabilitiesFairValueDisclosure" xlink:label="LiabilitiesFairValueDisclosure" xlink:title="LiabilitiesFairValueDisclosure" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LiabilitiesFairValueDisclosureAbstract" xlink:to="LiabilitiesFairValueDisclosure" xlink:title="definition: LiabilitiesFairValueDisclosureAbstract to LiabilitiesFairValueDisclosure" use="optional" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://www.mistrasgroup.com/role/DisclosureCapitalizationDetails2">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" use="optional" order="1.0" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_PlanNameAxis" xlink:label="PlanNameAxis" xlink:title="PlanNameAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="PlanNameAxis" xlink:title="definition: ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable to PlanNameAxis" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="PlanNameDomain" xlink:title="PlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="PlanNameAxis" xlink:to="PlanNameDomain" xlink:title="definition: PlanNameAxis to PlanNameDomain" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="PlanNameDomain_2" xlink:title="PlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="PlanNameAxis" xlink:to="PlanNameDomain_2" xlink:title="definition: PlanNameAxis to PlanNameDomain" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_LongTermIncentivePlan2009Member" xlink:label="LongTermIncentivePlan2009Member" xlink:title="LongTermIncentivePlan2009Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PlanNameDomain" xlink:to="LongTermIncentivePlan2009Member" xlink:title="definition: PlanNameDomain to LongTermIncentivePlan2009Member" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="AwardTypeAxis" xlink:title="AwardTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="AwardTypeAxis" xlink:title="definition: ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable to AwardTypeAxis" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="AwardTypeAxis" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:title="definition: AwardTypeAxis to ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="AwardTypeAxis" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" xlink:title="definition: AwardTypeAxis to ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="EmployeeStockOptionMember" xlink:title="EmployeeStockOptionMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="EmployeeStockOptionMember" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to EmployeeStockOptionMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember" xlink:label="RestrictedStockUnitsRSUMember" xlink:title="RestrictedStockUnitsRSUMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="RestrictedStockUnitsRSUMember" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to RestrictedStockUnitsRSUMember" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_IncentiveStockOptionsMember" xlink:label="IncentiveStockOptionsMember" xlink:title="IncentiveStockOptionsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="IncentiveStockOptionsMember" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to IncentiveStockOptionsMember" use="optional" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_NonqualifiedStockOptionsMember" xlink:label="NonqualifiedStockOptionsMember" xlink:title="NonqualifiedStockOptionsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="NonqualifiedStockOptionsMember" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to NonqualifiedStockOptionsMember" use="optional" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" xlink:label="SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" xlink:title="SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" use="optional" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" use="optional" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" use="optional" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfPlansPriorToInitialPublicOffering" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfPlansPriorToInitialPublicOffering" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfPlansPriorToInitialPublicOffering" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfPlansPriorToInitialPublicOffering" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfPlansPriorToInitialPublicOffering" use="optional" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized" use="optional" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" use="optional" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" use="optional" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:label="AllocatedShareBasedCompensationExpense" xlink:title="AllocatedShareBasedCompensationExpense" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="AllocatedShareBasedCompensationExpense" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to AllocatedShareBasedCompensationExpense" use="optional" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions" xlink:label="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions" xlink:title="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions" use="optional" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:label="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:title="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" use="optional" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAdditionalGeneralDisclosuresAbstract" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardAdditionalGeneralDisclosuresAbstract" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardAdditionalGeneralDisclosuresAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardAdditionalGeneralDisclosuresAbstract" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardAdditionalGeneralDisclosuresAbstract" use="optional" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationCashReceivedFromExerciseOfStockOptions" xlink:label="EmployeeServiceShareBasedCompensationCashReceivedFromExerciseOfStockOptions" xlink:title="EmployeeServiceShareBasedCompensationCashReceivedFromExerciseOfStockOptions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardAdditionalGeneralDisclosuresAbstract" xlink:to="EmployeeServiceShareBasedCompensationCashReceivedFromExerciseOfStockOptions" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardAdditionalGeneralDisclosuresAbstract to EmployeeServiceShareBasedCompensationCashReceivedFromExerciseOfStockOptions" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardAdditionalGeneralDisclosuresAbstract" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardAdditionalGeneralDisclosuresAbstract to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" use="optional" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://www.mistrasgroup.com/role/DisclosureCapitalizationDetails3">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" order="1.0" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="AwardTypeAxis" xlink:title="AwardTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="AwardTypeAxis" xlink:title="definition: ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable to AwardTypeAxis" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="AwardTypeAxis" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:title="definition: AwardTypeAxis to ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="EmployeeStockOptionMember" xlink:title="EmployeeStockOptionMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="EmployeeStockOptionMember" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to EmployeeStockOptionMember" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:title="StockIssuedDuringPeriodSharesStockOptionsExercised" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:to="StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward to StockIssuedDuringPeriodSharesStockOptionsExercised" use="optional" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod" use="optional" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" use="optional" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward to ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward to ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" use="optional" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice" use="optional" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" use="optional" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" use="optional" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://www.mistrasgroup.com/role/DisclosureCapitalizationDetails5">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" order="1.0" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="AwardTypeAxis" xlink:title="AwardTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="AwardTypeAxis" xlink:title="definition: ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable to AwardTypeAxis" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="AwardTypeAxis" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:title="definition: AwardTypeAxis to ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember" xlink:label="RestrictedStockUnitsRSUMember" xlink:title="RestrictedStockUnitsRSUMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="RestrictedStockUnitsRSUMember" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to RestrictedStockUnitsRSUMember" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_TitleOfIndividualAxis" xlink:label="TitleOfIndividualAxis" xlink:title="TitleOfIndividualAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="TitleOfIndividualAxis" xlink:title="definition: ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable to TitleOfIndividualAxis" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="TitleOfIndividualWithRelationshipToEntityDomain" xlink:title="TitleOfIndividualWithRelationshipToEntityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="TitleOfIndividualAxis" xlink:to="TitleOfIndividualWithRelationshipToEntityDomain" xlink:title="definition: TitleOfIndividualAxis to TitleOfIndividualWithRelationshipToEntityDomain" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="TitleOfIndividualWithRelationshipToEntityDomain_2" xlink:title="TitleOfIndividualWithRelationshipToEntityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="TitleOfIndividualAxis" xlink:to="TitleOfIndividualWithRelationshipToEntityDomain_2" xlink:title="definition: TitleOfIndividualAxis to TitleOfIndividualWithRelationshipToEntityDomain" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_DirectorMember" xlink:label="DirectorMember" xlink:title="DirectorMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TitleOfIndividualWithRelationshipToEntityDomain" xlink:to="DirectorMember" xlink:title="definition: TitleOfIndividualWithRelationshipToEntityDomain to DirectorMember" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:label="AllocatedShareBasedCompensationExpense" xlink:title="AllocatedShareBasedCompensationExpense" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="AllocatedShareBasedCompensationExpense" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to AllocatedShareBasedCompensationExpense" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:label="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:title="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" use="optional" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions" xlink:label="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions" xlink:title="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions" use="optional" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGranted" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGranted" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGranted" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGranted" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGranted" use="optional" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfNonEmployeeDirectorsToWhomAwardIsGranted" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfNonEmployeeDirectorsToWhomAwardIsGranted" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfNonEmployeeDirectorsToWhomAwardIsGranted" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfNonEmployeeDirectorsToWhomAwardIsGranted" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfNonEmployeeDirectorsToWhomAwardIsGranted" use="optional" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" use="optional" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue" use="optional" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation" xlink:label="SharesPaidForTaxWithholdingForShareBasedCompensation" xlink:title="SharesPaidForTaxWithholdingForShareBasedCompensation" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="SharesPaidForTaxWithholdingForShareBasedCompensation" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to SharesPaidForTaxWithholdingForShareBasedCompensation" use="optional" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation" xlink:label="PaymentsRelatedToTaxWithholdingForShareBasedCompensation" xlink:title="PaymentsRelatedToTaxWithholdingForShareBasedCompensation" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="PaymentsRelatedToTaxWithholdingForShareBasedCompensation" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to PaymentsRelatedToTaxWithholdingForShareBasedCompensation" use="optional" order="10.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://www.mistrasgroup.com/role/DisclosureCapitalizationDetails4">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1" xlink:label="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1" xlink:title="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" xlink:to="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract to SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:label="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:title="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable" xlink:label="ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable" xlink:title="ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:to="ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable" xlink:title="definition: ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems to ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable" order="1.0" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" xlink:label="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" xlink:title="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable" xlink:to="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" xlink:title="definition: ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable to ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" xlink:label="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" xlink:title="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" xlink:to="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" xlink:title="definition: ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis to ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" xlink:label="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_2" xlink:title="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" xlink:to="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_2" xlink:title="definition: ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis to ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_RangeOfExercisePricesFromDollars6.15To13.08Member" xlink:label="RangeOfExercisePricesFromDollars6.15To13.08Member" xlink:title="RangeOfExercisePricesFromDollars6.15To13.08Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" xlink:to="RangeOfExercisePricesFromDollars6.15To13.08Member" xlink:title="definition: ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain to RangeOfExercisePricesFromDollars6.15To13.08Member" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_RangeOfExercisePricesFromDollars13.09To22.35Member" xlink:label="RangeOfExercisePricesFromDollars13.09To22.35Member" xlink:title="RangeOfExercisePricesFromDollars13.09To22.35Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" xlink:to="RangeOfExercisePricesFromDollars13.09To22.35Member" xlink:title="definition: ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain to RangeOfExercisePricesFromDollars13.09To22.35Member" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit" xlink:label="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit" xlink:title="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:to="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit" xlink:title="definition: ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems to ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit" xlink:label="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit" xlink:title="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:to="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit" xlink:title="definition: ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems to ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit" use="optional" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsAbstract" xlink:label="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsAbstract" xlink:title="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:to="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsAbstract" xlink:title="definition: ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems to ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsAbstract" use="optional" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions" xlink:label="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions" xlink:title="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsAbstract" xlink:to="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions" xlink:title="definition: ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsAbstract to ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2" xlink:label="SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2" xlink:title="SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsAbstract" xlink:to="SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2" xlink:title="definition: ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsAbstract to SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1" xlink:label="SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1" xlink:title="SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsAbstract" xlink:to="SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1" xlink:title="definition: ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsAbstract to SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1" use="optional" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsAbstract" xlink:label="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsAbstract" xlink:title="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:to="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsAbstract" xlink:title="definition: ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems to ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsAbstract" use="optional" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions" xlink:label="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions" xlink:title="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsAbstract" xlink:to="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions" xlink:title="definition: ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsAbstract to ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1" xlink:label="SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1" xlink:title="SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsAbstract" xlink:to="SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1" xlink:title="definition: ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsAbstract to SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1" use="optional" order="2.0" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" xlink:title="definition: ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" use="optional" order="6.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://www.mistrasgroup.com/role/DisclosureCommitmentsAndContingenciesDetails">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_LossContingenciesLineItems" xlink:label="LossContingenciesLineItems" xlink:title="LossContingenciesLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_LossContingenciesTable" xlink:label="LossContingenciesTable" xlink:title="LossContingenciesTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="LossContingenciesLineItems" xlink:to="LossContingenciesTable" xlink:title="definition: LossContingenciesLineItems to LossContingenciesTable" use="optional" order="1.0" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_LossContingenciesByNatureOfContingencyAxis" xlink:label="LossContingenciesByNatureOfContingencyAxis" xlink:title="LossContingenciesByNatureOfContingencyAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="LossContingenciesTable" xlink:to="LossContingenciesByNatureOfContingencyAxis" xlink:title="definition: LossContingenciesTable to LossContingenciesByNatureOfContingencyAxis" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_LossContingencyNatureDomain" xlink:label="LossContingencyNatureDomain" xlink:title="LossContingencyNatureDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="LossContingenciesByNatureOfContingencyAxis" xlink:to="LossContingencyNatureDomain" xlink:title="definition: LossContingenciesByNatureOfContingencyAxis to LossContingencyNatureDomain" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_LossContingencyNatureDomain" xlink:label="LossContingencyNatureDomain_2" xlink:title="LossContingencyNatureDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="LossContingenciesByNatureOfContingencyAxis" xlink:to="LossContingencyNatureDomain_2" xlink:title="definition: LossContingenciesByNatureOfContingencyAxis to LossContingencyNatureDomain" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_LawsuitForDamagesResultingFromAllegedQualityDefectsMember" xlink:label="LawsuitForDamagesResultingFromAllegedQualityDefectsMember" xlink:title="LawsuitForDamagesResultingFromAllegedQualityDefectsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LossContingencyNatureDomain" xlink:to="LawsuitForDamagesResultingFromAllegedQualityDefectsMember" xlink:title="definition: LossContingencyNatureDomain to LawsuitForDamagesResultingFromAllegedQualityDefectsMember" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_AcquisitionRelatedContingenciesMember" xlink:label="AcquisitionRelatedContingenciesMember" xlink:title="AcquisitionRelatedContingenciesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LossContingencyNatureDomain" xlink:to="AcquisitionRelatedContingenciesMember" xlink:title="definition: LossContingencyNatureDomain to AcquisitionRelatedContingenciesMember" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_LossContingencyNumberOfLawsuitsYetToBeFiled" xlink:label="LossContingencyNumberOfLawsuitsYetToBeFiled" xlink:title="LossContingencyNumberOfLawsuitsYetToBeFiled" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LossContingenciesLineItems" xlink:to="LossContingencyNumberOfLawsuitsYetToBeFiled" xlink:title="definition: LossContingenciesLineItems to LossContingencyNumberOfLawsuitsYetToBeFiled" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueLow" xlink:label="BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueLow" xlink:title="BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueLow" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LossContingenciesLineItems" xlink:to="BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueLow" xlink:title="definition: LossContingenciesLineItems to BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueLow" use="optional" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh" xlink:label="BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh" xlink:title="BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LossContingenciesLineItems" xlink:to="BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh" xlink:title="definition: LossContingenciesLineItems to BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh" use="optional" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_BusinessCombinationContingentConsiderationPaymentPeriod" xlink:label="BusinessCombinationContingentConsiderationPaymentPeriod" xlink:title="BusinessCombinationContingentConsiderationPaymentPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LossContingenciesLineItems" xlink:to="BusinessCombinationContingentConsiderationPaymentPeriod" xlink:title="definition: LossContingenciesLineItems to BusinessCombinationContingentConsiderationPaymentPeriod" use="optional" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_LossContingencyClaimsSettledAndDismissedNumber" xlink:label="LossContingencyClaimsSettledAndDismissedNumber" xlink:title="LossContingencyClaimsSettledAndDismissedNumber" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LossContingenciesLineItems" xlink:to="LossContingencyClaimsSettledAndDismissedNumber" xlink:title="definition: LossContingenciesLineItems to LossContingencyClaimsSettledAndDismissedNumber" use="optional" order="8000.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_LossContingencyLossInPeriod" xlink:label="LossContingencyLossInPeriod" xlink:title="LossContingencyLossInPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LossContingenciesLineItems" xlink:to="LossContingencyLossInPeriod" xlink:title="definition: LossContingenciesLineItems to LossContingencyLossInPeriod" use="optional" order="8001.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://www.mistrasgroup.com/role/DisclosureSegmentDisclosureDetails2">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems" xlink:label="RevenuesFromExternalCustomersAndLongLivedAssetsLineItems" xlink:title="RevenuesFromExternalCustomersAndLongLivedAssetsLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable" xlink:label="ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable" xlink:title="ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="RevenuesFromExternalCustomersAndLongLivedAssetsLineItems" xlink:to="ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable" xlink:title="definition: RevenuesFromExternalCustomersAndLongLivedAssetsLineItems to ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable" order="1.0" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_StatementGeographicalAxis" xlink:label="StatementGeographicalAxis" xlink:title="StatementGeographicalAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable" xlink:to="StatementGeographicalAxis" xlink:title="definition: ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable to StatementGeographicalAxis" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:label="SegmentGeographicalDomain" xlink:title="SegmentGeographicalDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementGeographicalAxis" xlink:to="SegmentGeographicalDomain" xlink:title="definition: StatementGeographicalAxis to SegmentGeographicalDomain" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:label="SegmentGeographicalDomain_2" xlink:title="SegmentGeographicalDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementGeographicalAxis" xlink:to="SegmentGeographicalDomain_2" xlink:title="definition: StatementGeographicalAxis to SegmentGeographicalDomain" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/country/2013/country-2013-01-31.xsd#country_US" xlink:label="US" xlink:title="US" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentGeographicalDomain" xlink:to="US" xlink:title="definition: SegmentGeographicalDomain to US" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_OtherAmericasMember" xlink:label="OtherAmericasMember" xlink:title="OtherAmericasMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentGeographicalDomain" xlink:to="OtherAmericasMember" xlink:title="definition: SegmentGeographicalDomain to OtherAmericasMember" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_EuropeMember" xlink:label="EuropeMember" xlink:title="EuropeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentGeographicalDomain" xlink:to="EuropeMember" xlink:title="definition: SegmentGeographicalDomain to EuropeMember" use="optional" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_AsiaPacificMember" xlink:label="AsiaPacificMember" xlink:title="AsiaPacificMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentGeographicalDomain" xlink:to="AsiaPacificMember" xlink:title="definition: SegmentGeographicalDomain to AsiaPacificMember" use="optional" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_SalesRevenueNet" xlink:label="SalesRevenueNet" xlink:title="SalesRevenueNet" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RevenuesFromExternalCustomersAndLongLivedAssetsLineItems" xlink:to="SalesRevenueNet" xlink:title="definition: RevenuesFromExternalCustomersAndLongLivedAssetsLineItems to SalesRevenueNet" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_NoncurrentAssets" xlink:label="NoncurrentAssets" xlink:title="NoncurrentAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RevenuesFromExternalCustomersAndLongLivedAssetsLineItems" xlink:to="NoncurrentAssets" xlink:title="definition: RevenuesFromExternalCustomersAndLongLivedAssetsLineItems to NoncurrentAssets" order="3.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://www.mistrasgroup.com/role/DisclosureEarningsPerShareDetails">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:label="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:title="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" xlink:label="ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" xlink:title="ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:to="ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" xlink:title="definition: AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems to ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" order="1.0" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:label="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:title="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" xlink:to="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:title="definition: ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable to AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:label="AntidilutiveSecuritiesNameDomain" xlink:title="AntidilutiveSecuritiesNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:to="AntidilutiveSecuritiesNameDomain" xlink:title="definition: AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis to AntidilutiveSecuritiesNameDomain" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:label="AntidilutiveSecuritiesNameDomain_2" xlink:title="AntidilutiveSecuritiesNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:to="AntidilutiveSecuritiesNameDomain_2" xlink:title="definition: AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis to AntidilutiveSecuritiesNameDomain" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="EmployeeStockOptionMember" xlink:title="EmployeeStockOptionMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AntidilutiveSecuritiesNameDomain" xlink:to="EmployeeStockOptionMember" xlink:title="definition: AntidilutiveSecuritiesNameDomain to EmployeeStockOptionMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:label="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:title="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:to="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:title="definition: AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems to AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" use="optional" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://www.mistrasgroup.com/role/DisclosureSummaryOfSignificantAccountingPoliciesDetails2">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ConcentrationRiskLineItems" xlink:label="ConcentrationRiskLineItems" xlink:title="ConcentrationRiskLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ConcentrationRiskTable" xlink:label="ConcentrationRiskTable" xlink:title="ConcentrationRiskTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ConcentrationRiskLineItems" xlink:to="ConcentrationRiskTable" xlink:title="definition: ConcentrationRiskLineItems to ConcentrationRiskTable" use="optional" order="1.0" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:label="ConcentrationRiskByBenchmarkAxis" xlink:title="ConcentrationRiskByBenchmarkAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ConcentrationRiskTable" xlink:to="ConcentrationRiskByBenchmarkAxis" xlink:title="definition: ConcentrationRiskTable to ConcentrationRiskByBenchmarkAxis" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="ConcentrationRiskBenchmarkDomain" xlink:title="ConcentrationRiskBenchmarkDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ConcentrationRiskByBenchmarkAxis" xlink:to="ConcentrationRiskBenchmarkDomain" xlink:title="definition: ConcentrationRiskByBenchmarkAxis to ConcentrationRiskBenchmarkDomain" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="ConcentrationRiskBenchmarkDomain_2" xlink:title="ConcentrationRiskBenchmarkDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ConcentrationRiskByBenchmarkAxis" xlink:to="ConcentrationRiskBenchmarkDomain_2" xlink:title="definition: ConcentrationRiskByBenchmarkAxis to ConcentrationRiskBenchmarkDomain" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_SalesMember" xlink:label="SalesMember" xlink:title="SalesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConcentrationRiskBenchmarkDomain" xlink:to="SalesMember" xlink:title="definition: ConcentrationRiskBenchmarkDomain to SalesMember" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_AccountsReceivableMember" xlink:label="AccountsReceivableMember" xlink:title="AccountsReceivableMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConcentrationRiskBenchmarkDomain" xlink:to="AccountsReceivableMember" xlink:title="definition: ConcentrationRiskBenchmarkDomain to AccountsReceivableMember" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ConcentrationRiskByTypeAxis" xlink:label="ConcentrationRiskByTypeAxis" xlink:title="ConcentrationRiskByTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ConcentrationRiskTable" xlink:to="ConcentrationRiskByTypeAxis" xlink:title="definition: ConcentrationRiskTable to ConcentrationRiskByTypeAxis" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="ConcentrationRiskTypeDomain" xlink:title="ConcentrationRiskTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ConcentrationRiskByTypeAxis" xlink:to="ConcentrationRiskTypeDomain" xlink:title="definition: ConcentrationRiskByTypeAxis to ConcentrationRiskTypeDomain" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="ConcentrationRiskTypeDomain_2" xlink:title="ConcentrationRiskTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ConcentrationRiskByTypeAxis" xlink:to="ConcentrationRiskTypeDomain_2" xlink:title="definition: ConcentrationRiskByTypeAxis to ConcentrationRiskTypeDomain" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_CustomerConcentrationRiskMember" xlink:label="CustomerConcentrationRiskMember" xlink:title="CustomerConcentrationRiskMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConcentrationRiskTypeDomain" xlink:to="CustomerConcentrationRiskMember" xlink:title="definition: ConcentrationRiskTypeDomain to CustomerConcentrationRiskMember" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_MajorCustomersAxis" xlink:label="MajorCustomersAxis" xlink:title="MajorCustomersAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ConcentrationRiskTable" xlink:to="MajorCustomersAxis" xlink:title="definition: ConcentrationRiskTable to MajorCustomersAxis" use="optional" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_NameOfMajorCustomerDomain" xlink:label="NameOfMajorCustomerDomain" xlink:title="NameOfMajorCustomerDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="MajorCustomersAxis" xlink:to="NameOfMajorCustomerDomain" xlink:title="definition: MajorCustomersAxis to NameOfMajorCustomerDomain" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_NameOfMajorCustomerDomain" xlink:label="NameOfMajorCustomerDomain_2" xlink:title="NameOfMajorCustomerDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="MajorCustomersAxis" xlink:to="NameOfMajorCustomerDomain_2" xlink:title="definition: MajorCustomersAxis to NameOfMajorCustomerDomain" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_BPPlcMember" xlink:label="BPPlcMember" xlink:title="BPPlcMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NameOfMajorCustomerDomain" xlink:to="BPPlcMember" xlink:title="definition: NameOfMajorCustomerDomain to BPPlcMember" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_ConcentrationRiskNumberOfCustomers" xlink:label="ConcentrationRiskNumberOfCustomers" xlink:title="ConcentrationRiskNumberOfCustomers" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConcentrationRiskLineItems" xlink:to="ConcentrationRiskNumberOfCustomers" xlink:title="definition: ConcentrationRiskLineItems to ConcentrationRiskNumberOfCustomers" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ConcentrationRiskPercentage1" xlink:label="ConcentrationRiskPercentage1" xlink:title="ConcentrationRiskPercentage1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConcentrationRiskLineItems" xlink:to="ConcentrationRiskPercentage1" xlink:title="definition: ConcentrationRiskLineItems to ConcentrationRiskPercentage1" use="optional" order="3.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://www.mistrasgroup.com/role/DisclosureSegmentDisclosureDetails3">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ConcentrationRiskLineItems" xlink:label="ConcentrationRiskLineItems" xlink:title="ConcentrationRiskLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ConcentrationRiskTable" xlink:label="ConcentrationRiskTable" xlink:title="ConcentrationRiskTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ConcentrationRiskLineItems" xlink:to="ConcentrationRiskTable" xlink:title="definition: ConcentrationRiskLineItems to ConcentrationRiskTable" use="optional" order="1.0" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:label="ConcentrationRiskByBenchmarkAxis" xlink:title="ConcentrationRiskByBenchmarkAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ConcentrationRiskTable" xlink:to="ConcentrationRiskByBenchmarkAxis" xlink:title="definition: ConcentrationRiskTable to ConcentrationRiskByBenchmarkAxis" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="ConcentrationRiskBenchmarkDomain" xlink:title="ConcentrationRiskBenchmarkDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ConcentrationRiskByBenchmarkAxis" xlink:to="ConcentrationRiskBenchmarkDomain" xlink:title="definition: ConcentrationRiskByBenchmarkAxis to ConcentrationRiskBenchmarkDomain" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_LongLivedAssetsMember" xlink:label="LongLivedAssetsMember" xlink:title="LongLivedAssetsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConcentrationRiskBenchmarkDomain" xlink:to="LongLivedAssetsMember" xlink:title="definition: ConcentrationRiskBenchmarkDomain to LongLivedAssetsMember" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ConcentrationRiskByTypeAxis" xlink:label="ConcentrationRiskByTypeAxis" xlink:title="ConcentrationRiskByTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ConcentrationRiskTable" xlink:to="ConcentrationRiskByTypeAxis" xlink:title="definition: ConcentrationRiskTable to ConcentrationRiskByTypeAxis" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="ConcentrationRiskTypeDomain" xlink:title="ConcentrationRiskTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ConcentrationRiskByTypeAxis" xlink:to="ConcentrationRiskTypeDomain" xlink:title="definition: ConcentrationRiskByTypeAxis to ConcentrationRiskTypeDomain" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_GeographicConcentrationRiskMember" xlink:label="GeographicConcentrationRiskMember" xlink:title="GeographicConcentrationRiskMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ConcentrationRiskTypeDomain" xlink:to="GeographicConcentrationRiskMember" xlink:title="definition: ConcentrationRiskTypeDomain to GeographicConcentrationRiskMember" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_CountryAxis" xlink:label="CountryAxis" xlink:title="CountryAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ConcentrationRiskTable" xlink:to="CountryAxis" xlink:title="definition: ConcentrationRiskTable to CountryAxis" use="optional" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/country/2013/country-2013-01-31.xsd#country_AllCountriesDomain" xlink:label="AllCountriesDomain" xlink:title="AllCountriesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="CountryAxis" xlink:to="AllCountriesDomain" xlink:title="definition: CountryAxis to AllCountriesDomain" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/country/2013/country-2013-01-31.xsd#country_AllCountriesDomain" xlink:label="AllCountriesDomain_2" xlink:title="AllCountriesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="CountryAxis" xlink:to="AllCountriesDomain_2" xlink:title="definition: CountryAxis to AllCountriesDomain" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/country/2013/country-2013-01-31.xsd#country_BR" xlink:label="BR" xlink:title="BR" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllCountriesDomain" xlink:to="BR" xlink:title="definition: AllCountriesDomain to BR" use="optional" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://www.mistrasgroup.com/role/DisclosureGoodwillDetails">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="StatementBusinessSegmentsAxis" xlink:title="StatementBusinessSegmentsAxis" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_SegmentDomain" xlink:label="SegmentDomain" xlink:title="SegmentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementBusinessSegmentsAxis" xlink:to="SegmentDomain" xlink:title="definition: StatementBusinessSegmentsAxis to SegmentDomain" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_InternationalMember" xlink:label="InternationalMember" xlink:title="InternationalMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentDomain" xlink:to="InternationalMember" xlink:title="definition: SegmentDomain to InternationalMember" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_ServicesMember" xlink:label="ServicesMember" xlink:title="ServicesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentDomain" xlink:to="ServicesMember" xlink:title="definition: SegmentDomain to ServicesMember" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_ProductsAndSystemsMember" xlink:label="ProductsAndSystemsMember" xlink:title="ProductsAndSystemsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentDomain" xlink:to="ProductsAndSystemsMember" xlink:title="definition: SegmentDomain to ProductsAndSystemsMember" use="optional" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_GoodwillLineItems" xlink:label="GoodwillLineItems" xlink:title="GoodwillLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ScheduleOfGoodwillTable" xlink:label="ScheduleOfGoodwillTable" xlink:title="ScheduleOfGoodwillTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="GoodwillLineItems" xlink:to="ScheduleOfGoodwillTable" xlink:title="definition: GoodwillLineItems to ScheduleOfGoodwillTable" order="1.0" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfGoodwillTable" xlink:to="StatementBusinessSegmentsAxis" xlink:title="definition: ScheduleOfGoodwillTable to StatementBusinessSegmentsAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_GoodwillRollForward" xlink:label="GoodwillRollForward" xlink:title="GoodwillRollForward" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="GoodwillLineItems" xlink:to="GoodwillRollForward" xlink:title="definition: GoodwillLineItems to GoodwillRollForward" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_GoodwillAcquiredDuringPeriod" xlink:label="GoodwillAcquiredDuringPeriod" xlink:title="GoodwillAcquiredDuringPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="GoodwillRollForward" xlink:to="GoodwillAcquiredDuringPeriod" xlink:title="definition: GoodwillRollForward to GoodwillAcquiredDuringPeriod" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_GoodwillPurchaseAccountingAdjustments" xlink:label="GoodwillPurchaseAccountingAdjustments" xlink:title="GoodwillPurchaseAccountingAdjustments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="GoodwillRollForward" xlink:to="GoodwillPurchaseAccountingAdjustments" xlink:title="definition: GoodwillRollForward to GoodwillPurchaseAccountingAdjustments" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_GoodwillImpairmentLoss" xlink:label="GoodwillImpairmentLoss" xlink:title="GoodwillImpairmentLoss" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="GoodwillRollForward" xlink:to="GoodwillImpairmentLoss" xlink:title="definition: GoodwillRollForward to GoodwillImpairmentLoss" use="optional" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_GoodwillTranslationAdjustments" xlink:label="GoodwillTranslationAdjustments" xlink:title="GoodwillTranslationAdjustments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="GoodwillRollForward" xlink:to="GoodwillTranslationAdjustments" xlink:title="definition: GoodwillRollForward to GoodwillTranslationAdjustments" use="optional" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_Goodwill" xlink:label="Goodwill" xlink:title="Goodwill" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="GoodwillRollForward" xlink:to="Goodwill" xlink:title="definition: GoodwillRollForward to Goodwill" use="optional" order="5.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://www.mistrasgroup.com/role/DisclosureSummaryOfSignificantAccountingPoliciesDetails3">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="StatementBusinessSegmentsAxis" xlink:title="StatementBusinessSegmentsAxis" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_SegmentDomain" xlink:label="SegmentDomain" xlink:title="SegmentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementBusinessSegmentsAxis" xlink:to="SegmentDomain" xlink:title="definition: StatementBusinessSegmentsAxis to SegmentDomain" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="mg-20130531.xsd#mg_InternationalMember" xlink:label="InternationalMember" xlink:title="InternationalMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentDomain" xlink:to="InternationalMember" xlink:title="definition: SegmentDomain to InternationalMember" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_StatementGeographicalAxis" xlink:label="StatementGeographicalAxis" xlink:title="StatementGeographicalAxis" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:label="SegmentGeographicalDomain" xlink:title="SegmentGeographicalDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementGeographicalAxis" xlink:to="SegmentGeographicalDomain" xlink:title="definition: StatementGeographicalAxis to SegmentGeographicalDomain" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/country/2013/country-2013-01-31.xsd#country_BR" xlink:label="BR" xlink:title="BR" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentGeographicalDomain" xlink:to="BR" xlink:title="definition: SegmentGeographicalDomain to BR" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_GoodwillLineItems" xlink:label="GoodwillLineItems" xlink:title="GoodwillLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ScheduleOfGoodwillTable" xlink:label="ScheduleOfGoodwillTable" xlink:title="ScheduleOfGoodwillTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="GoodwillLineItems" xlink:to="ScheduleOfGoodwillTable" xlink:title="definition: GoodwillLineItems to ScheduleOfGoodwillTable" use="optional" order="1.0" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfGoodwillTable" xlink:to="StatementBusinessSegmentsAxis" xlink:title="definition: ScheduleOfGoodwillTable to StatementBusinessSegmentsAxis" use="optional" order="1.0" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfGoodwillTable" xlink:to="StatementGeographicalAxis" xlink:title="definition: ScheduleOfGoodwillTable to StatementGeographicalAxis" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_Goodwill" xlink:label="Goodwill" xlink:title="Goodwill" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="GoodwillLineItems" xlink:to="Goodwill" xlink:title="definition: GoodwillLineItems to Goodwill" use="optional" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_GoodwillImpairmentLoss" xlink:label="GoodwillImpairmentLoss" xlink:title="GoodwillImpairmentLoss" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="GoodwillLineItems" xlink:to="GoodwillImpairmentLoss" xlink:title="definition: GoodwillLineItems to GoodwillImpairmentLoss" use="optional" order="3.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://www.mistrasgroup.com/role/DisclosureEmployeeBenefitPlansDetails2">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_RangeAxis" xlink:label="RangeAxis" xlink:title="RangeAxis" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_RangeMember" xlink:label="RangeMember" xlink:title="RangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RangeAxis" xlink:to="RangeMember" xlink:title="definition: RangeAxis to RangeMember" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_MaximumMember" xlink:label="MaximumMember" xlink:title="MaximumMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MaximumMember" xlink:title="definition: RangeMember to MaximumMember" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_MultiemployerPlansLineItems" xlink:label="MultiemployerPlansLineItems" xlink:title="MultiemployerPlansLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ScheduleOfMultiemployerPlansTable" xlink:label="ScheduleOfMultiemployerPlansTable" xlink:title="ScheduleOfMultiemployerPlansTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="MultiemployerPlansLineItems" xlink:to="ScheduleOfMultiemployerPlansTable" xlink:title="definition: MultiemployerPlansLineItems to ScheduleOfMultiemployerPlansTable" use="optional" order="2.0" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfMultiemployerPlansTable" xlink:to="RangeAxis" xlink:title="definition: ScheduleOfMultiemployerPlansTable to RangeAxis" use="optional" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_MultiemployerPlanPeriodContributions" xlink:label="MultiemployerPlanPeriodContributions" xlink:title="MultiemployerPlanPeriodContributions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="MultiemployerPlansLineItems" xlink:to="MultiemployerPlanPeriodContributions" xlink:title="definition: MultiemployerPlansLineItems to MultiemployerPlanPeriodContributions" use="optional" order="3.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://www.mistrasgroup.com/role/StatementOfStockholdersEquity">
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_StatementLineItems" xlink:label="StatementLineItems" xlink:title="StatementLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_StatementTable" xlink:label="StatementTable" xlink:title="StatementTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="StatementLineItems" xlink:to="StatementTable" xlink:title="definition: StatementLineItems to StatementTable" order="10.0" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="StatementEquityComponentsAxis" xlink:title="StatementEquityComponentsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="StatementTable" xlink:to="StatementEquityComponentsAxis" xlink:title="definition: StatementTable to StatementEquityComponentsAxis" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="EquityComponentDomain" xlink:title="EquityComponentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementEquityComponentsAxis" xlink:to="EquityComponentDomain" xlink:title="definition: StatementEquityComponentsAxis to EquityComponentDomain" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="EquityComponentDomain_2" xlink:title="EquityComponentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementEquityComponentsAxis" xlink:to="EquityComponentDomain_2" xlink:title="definition: StatementEquityComponentsAxis to EquityComponentDomain" order="20.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ParentMember" xlink:label="ParentMember" xlink:title="ParentMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="ParentMember" xlink:title="definition: EquityComponentDomain to ParentMember" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_CommonStockMember" xlink:label="CommonStockMember" xlink:title="CommonStockMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ParentMember" xlink:to="CommonStockMember" xlink:title="definition: ParentMember to CommonStockMember" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember" xlink:label="AdditionalPaidInCapitalMember" xlink:title="AdditionalPaidInCapitalMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ParentMember" xlink:to="AdditionalPaidInCapitalMember" xlink:title="definition: ParentMember to AdditionalPaidInCapitalMember" order="20.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_RetainedEarningsMember" xlink:label="RetainedEarningsMember" xlink:title="RetainedEarningsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ParentMember" xlink:to="RetainedEarningsMember" xlink:title="definition: ParentMember to RetainedEarningsMember" order="30.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:label="AccumulatedOtherComprehensiveIncomeMember" xlink:title="AccumulatedOtherComprehensiveIncomeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ParentMember" xlink:to="AccumulatedOtherComprehensiveIncomeMember" xlink:title="definition: ParentMember to AccumulatedOtherComprehensiveIncomeMember" order="40.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_NoncontrollingInterestMember" xlink:label="NoncontrollingInterestMember" xlink:title="NoncontrollingInterestMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="NoncontrollingInterestMember" xlink:title="definition: EquityComponentDomain to NoncontrollingInterestMember" order="20.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ComprehensiveIncomeMember" xlink:label="ComprehensiveIncomeMember" xlink:title="ComprehensiveIncomeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="ComprehensiveIncomeMember" xlink:title="definition: EquityComponentDomain to ComprehensiveIncomeMember" use="optional" order="8000.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xlink:label="IncreaseDecreaseInStockholdersEquityRollForward" xlink:title="IncreaseDecreaseInStockholdersEquityRollForward" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="IncreaseDecreaseInStockholdersEquityRollForward" xlink:title="definition: StatementLineItems to IncreaseDecreaseInStockholdersEquityRollForward" order="20.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_ProfitLoss" xlink:label="ProfitLoss" xlink:title="ProfitLoss" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="ProfitLoss" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to ProfitLoss" use="optional" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:label="OtherComprehensiveIncomeLossNetOfTax" xlink:title="OtherComprehensiveIncomeLossNetOfTax" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="OtherComprehensiveIncomeLossNetOfTax" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to OtherComprehensiveIncomeLossNetOfTax" use="optional" order="20.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:label="AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:title="AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" use="optional" order="40.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:label="StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:title="StockIssuedDuringPeriodSharesShareBasedCompensation" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:to="StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:title="definition: AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue to StockIssuedDuringPeriodSharesShareBasedCompensation" use="optional" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation" xlink:label="AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation" xlink:title="AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation" use="optional" order="50.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures" xlink:label="StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures" xlink:title="StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation" xlink:to="StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures" xlink:title="definition: AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation to StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures" use="optional" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation" xlink:label="AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation" xlink:title="AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation" use="optional" order="60.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised" xlink:label="StockIssuedDuringPeriodValueStockOptionsExercised" xlink:title="StockIssuedDuringPeriodValueStockOptionsExercised" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="StockIssuedDuringPeriodValueStockOptionsExercised" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to StockIssuedDuringPeriodValueStockOptionsExercised" use="optional" order="70.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:title="StockIssuedDuringPeriodSharesStockOptionsExercised" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StockIssuedDuringPeriodValueStockOptionsExercised" xlink:to="StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:title="definition: StockIssuedDuringPeriodValueStockOptionsExercised to StockIssuedDuringPeriodSharesStockOptionsExercised" use="optional" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance" xlink:label="NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance" xlink:title="NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance" order="80.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:label="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:title="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" use="optional" order="90.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_SharesIssued" xlink:label="SharesIssued" xlink:title="SharesIssued" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="SharesIssued" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to SharesIssued" use="optional" order="100.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_StockholdersEquityPeriodIncreaseDecrease" xlink:label="StockholdersEquityPeriodIncreaseDecrease" xlink:title="StockholdersEquityPeriodIncreaseDecrease" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="StockholdersEquityPeriodIncreaseDecrease" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to StockholdersEquityPeriodIncreaseDecrease" use="optional" order="110.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesPeriodIncreaseDecrease" xlink:label="StockIssuedDuringPeriodSharesPeriodIncreaseDecrease" xlink:title="StockIssuedDuringPeriodSharesPeriodIncreaseDecrease" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StockholdersEquityPeriodIncreaseDecrease" xlink:to="StockIssuedDuringPeriodSharesPeriodIncreaseDecrease" xlink:title="definition: StockholdersEquityPeriodIncreaseDecrease to StockIssuedDuringPeriodSharesPeriodIncreaseDecrease" use="optional" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_PreferredStockAccretionOfRedemptionDiscount" xlink:label="PreferredStockAccretionOfRedemptionDiscount" xlink:title="PreferredStockAccretionOfRedemptionDiscount" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="PreferredStockAccretionOfRedemptionDiscount" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to PreferredStockAccretionOfRedemptionDiscount" use="optional" order="8000.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities" xlink:label="StockIssuedDuringPeriodValueConversionOfConvertibleSecurities" xlink:title="StockIssuedDuringPeriodValueConversionOfConvertibleSecurities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="StockIssuedDuringPeriodValueConversionOfConvertibleSecurities" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to StockIssuedDuringPeriodValueConversionOfConvertibleSecurities" use="optional" order="8010.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities" xlink:label="StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities" xlink:title="StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StockIssuedDuringPeriodValueConversionOfConvertibleSecurities" xlink:to="StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities" xlink:title="definition: StockIssuedDuringPeriodValueConversionOfConvertibleSecurities to StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities" use="optional" order="8000.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_StockholdersEquityOther" xlink:label="StockholdersEquityOther" xlink:title="StockholdersEquityOther" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="StockholdersEquityOther" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to StockholdersEquityOther" use="optional" order="8020.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:label="StockIssuedDuringPeriodValueNewIssues" xlink:title="StockIssuedDuringPeriodValueNewIssues" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="StockIssuedDuringPeriodValueNewIssues" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to StockIssuedDuringPeriodValueNewIssues" use="optional" order="8030.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract" xlink:label="OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract" xlink:title="OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract" use="optional" order="8040.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_SaleOfStockConsiderationReceivedOnTransaction" xlink:label="SaleOfStockConsiderationReceivedOnTransaction" xlink:title="SaleOfStockConsiderationReceivedOnTransaction" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="SaleOfStockConsiderationReceivedOnTransaction" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to SaleOfStockConsiderationReceivedOnTransaction" order="30.0" />
    <link:loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2013/elts/us-gaap-2013-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:label="StockIssuedDuringPeriodSharesNewIssues" xlink:title="StockIssuedDuringPeriodSharesNewIssues" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SaleOfStockConsiderationReceivedOnTransaction" xlink:to="StockIssuedDuringPeriodSharesNewIssues" xlink:title="definition: SaleOfStockConsiderationReceivedOnTransaction to StockIssuedDuringPeriodSharesNewIssues" use="optional" order="10.0" />
  </link:definitionLink>
</link:linkbase>
