<SEC-DOCUMENT>0000866273-14-000084.txt : 20140828
<SEC-HEADER>0000866273-14-000084.hdr.sgml : 20140828
<ACCEPTANCE-DATETIME>20140828144606
ACCESSION NUMBER:		0000866273-14-000084
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20140826
FILED AS OF DATE:		20140828
DATE AS OF CHANGE:		20140828

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MATRIX SERVICE CO
		CENTRAL INDEX KEY:			0000866273
		STANDARD INDUSTRIAL CLASSIFICATION:	CONSTRUCTION SPECIAL TRADE CONTRACTORS [1700]
		IRS NUMBER:				731352174
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0630

	BUSINESS ADDRESS:	
		STREET 1:		5100 EAST SKELLY DRIVE
		STREET 2:		SUITE 700
		CITY:			TULSA
		STATE:			OK
		ZIP:			74135
		BUSINESS PHONE:		9188388822

	MAIL ADDRESS:	
		STREET 1:		5100 EAST SKELLY DRIVE
		STREET 2:		SUITE 700
		CITY:			TULSA
		STATE:			OK
		ZIP:			74135

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Cavanah Kevin S
		CENTRAL INDEX KEY:			0001409823

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-15461
		FILM NUMBER:		141071404

	MAIL ADDRESS:	
		STREET 1:		5100 EAST SKELLY DRIVE, SUITE 700
		CITY:			TULSA
		STATE:			OK
		ZIP:			74135
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_140925155557594.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2014-08-26</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000866273</issuerCik>
        <issuerName>MATRIX SERVICE CO</issuerName>
        <issuerTradingSymbol>MTRX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001409823</rptOwnerCik>
            <rptOwnerName>Cavanah Kevin S</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>5100 EAST SKELLY DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 700</rptOwnerStreet2>
            <rptOwnerCity>TULSA</rptOwnerCity>
            <rptOwnerState>OK</rptOwnerState>
            <rptOwnerZipCode>74135</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>VP Finance &amp; CFO</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>COMMON STOCK</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <transactionDate>
                <value>2014-08-26</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>6246</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>59830</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>COMMON STOCK</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <transactionDate>
                <value>2014-08-27</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>641</value>
                    <footnoteId id="F4"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>28.79</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>59189</value>
                    <footnoteId id="F5"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">MATRIX SERVICE COMPANY COMMON STOCK.</footnote>
        <footnote id="F2">RESTRICTED STOCK UNIT - EACH UNIT WILL ENTITLE THE REPORTING PERSON TO ONE SHARE OF MATRIX SERVICE COMPANY COMMON STOCK IF AND WHEN THE CONDITIONS OF THE RESTRICTION HAVE BEEN SATISFIED.  FOR THIS GRANT, 25% WILL VEST EACH YEAR FOR THE NEXT FOUR YEARS ON THE ANNIVERSARY DATES.</footnote>
        <footnote id="F3">NOT APPLICABLE.</footnote>
        <footnote id="F4">RESTRICTED STOCK UNIT AWARD - SHARES DISPOSED TO SATISFY TAX OBLIGATION DUE ON VEST DATE FOR TIME-BASED GRANT.</footnote>
        <footnote id="F5">INCLUDES 20,290 SHARES OF MATRIX SERVICE COMPANY COMMON STOCK OWNED OUTRIGHT.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Kevin S. Cavanah</signatureName>
        <signatureDate>2014-08-28</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
