<SEC-DOCUMENT>0001127602-21-011989.txt : 20210325
<SEC-HEADER>0001127602-21-011989.hdr.sgml : 20210325
<ACCEPTANCE-DATETIME>20210325094713
ACCESSION NUMBER:		0001127602-21-011989
CONFORMED SUBMISSION TYPE:	4/A
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20210316
FILED AS OF DATE:		20210325
DATE AS OF CHANGE:		20210325

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Wolk Jonathan H
		CENTRAL INDEX KEY:			0001311412

	FILING VALUES:
		FORM TYPE:		4/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-34481
		FILM NUMBER:		21770396

	MAIL ADDRESS:	
		STREET 1:		3102 SHAWNEE DRIVE
		CITY:			WINCHESTER
		STATE:			VA
		ZIP:			22601

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Mistras Group, Inc.
		CENTRAL INDEX KEY:			0001436126
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-ENGINEERING SERVICES [8711]
		IRS NUMBER:				223341267
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		195 CLARKSVILLE ROAD
		CITY:			PRINCETON JUNCTION
		STATE:			NJ
		ZIP:			08550
		BUSINESS PHONE:		609-716-4000

	MAIL ADDRESS:	
		STREET 1:		195 CLARKSVILLE ROAD
		CITY:			PRINCETON JUNCTION
		STATE:			NJ
		ZIP:			08550
</SEC-HEADER>
<DOCUMENT>
<TYPE>4/A
<SEQUENCE>1
<FILENAME>form4a.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2021-03-16</periodOfReport>

    <dateOfOriginalSubmission>2021-03-18</dateOfOriginalSubmission>

    <issuer>
        <issuerCik>0001436126</issuerCik>
        <issuerName>Mistras Group, Inc.</issuerName>
        <issuerTradingSymbol>MG</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001311412</rptOwnerCik>
            <rptOwnerName>Wolk Jonathan H</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O MISTRAS GROUP</rptOwnerStreet1>
            <rptOwnerStreet2>195 CLARKSVILLE ROAD</rptOwnerStreet2>
            <rptOwnerCity>PRINCETON JUNCTION</rptOwnerCity>
            <rptOwnerState>NJ</rptOwnerState>
            <rptOwnerZipCode>08550</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isOfficer>1</isOfficer>
            <officerTitle>Sr. EVP and COO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2021-03-16</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>13589</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>117749</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2021-03-16</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>14300</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>132049</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Transaction represents an award of restricted stock units for payment of a performance award earned, which vests 25% on March 16, 2022 and on December 31 in 2022, 2023 and 2024.</footnote>
        <footnote id="F2">Represents an award of restricted stock units that will vest 25% on each anniversary of the award.</footnote>
    </footnotes>

    <remarks>This amendment is made solely to add footnote 2.</remarks>

    <ownerSignature>
        <signatureName>/s/ Michael C. Keefe, attorney in fact for Jonathan H. Wolk</signatureName>
        <signatureDate>2021-03-24</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
