<SEC-DOCUMENT>0001127602-24-022475.txt : 20240819
<SEC-HEADER>0001127602-24-022475.hdr.sgml : 20240819
<ACCEPTANCE-DATETIME>20240819161507
ACCESSION NUMBER:		0001127602-24-022475
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20240703
FILED AS OF DATE:		20240819
DATE AS OF CHANGE:		20240819

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			GLANTON RICHARD H
		CENTRAL INDEX KEY:			0001060493
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-34481
		FILM NUMBER:		241220715

	MAIL ADDRESS:	
		STREET 1:		C/O THE GEO GROUP, INC.
		STREET 2:		4955 TECHNOLOGY WAY
		CITY:			BOCA RATON
		STATE:			FL
		ZIP:			33431

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Mistras Group, Inc.
		CENTRAL INDEX KEY:			0001436126
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-ENGINEERING SERVICES [8711]
		ORGANIZATION NAME:           	07 Trade & Services
		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
<SEQUENCE>1
<FILENAME>form4.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2024-07-03</periodOfReport>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001060493</rptOwnerCik>
            <rptOwnerName>GLANTON RICHARD H</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O MISTRAS GROUP, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>195 CLARKSVILLE ROAD</rptOwnerStreet2>
            <rptOwnerCity>PRINCETON JUNCTION</rptOwnerCity>
            <rptOwnerState>NJ</rptOwnerState>
            <rptOwnerZipCode>08850</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2024-08-07</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>5705</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>47822</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2024-07-03</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>G</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>700</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>41417</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2024-07-03</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>G</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>700</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2810</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Note</value>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Transaction represents an award of stock for director fees.</footnote>
        <footnote id="F2">Shares transferred to trust for Mr. Glanton's minor daughter, Mr. Glanton's spouse as trustee.</footnote>
        <footnote id="F3">Held in trust for Mr. Glanton's daughter; as trustee, Mr. Glanton's spouse has voting and dispositive power.</footnote>
    </footnotes>

    <remarks>The gift to the trust for Mr. Glanton's minor daughter is being voluntarily reported early rather than pursuant to a Form 5 after the end of calendar year 2024.</remarks>

    <ownerSignature>
        <signatureName>Michael C. Keefe, attorney-in-fact for Richard H. Glanton</signatureName>
        <signatureDate>2024-08-19</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
