<SEC-DOCUMENT>0001179110-17-015603.txt : 20171219
<SEC-HEADER>0001179110-17-015603.hdr.sgml : 20171219
<ACCEPTANCE-DATETIME>20171219142642
ACCESSION NUMBER:		0001179110-17-015603
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20171215
FILED AS OF DATE:		20171219
DATE AS OF CHANGE:		20171219

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Chow Daniel
		CENTRAL INDEX KEY:			0001452377

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-33076
		FILM NUMBER:		171263687

	MAIL ADDRESS:	
		STREET 1:		2401 EAST KATELLA AVENUE
		STREET 2:		SUITE 300
		CITY:			ANAHEIM
		STATE:			CA
		ZIP:			92806

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Willdan Group, Inc.
		CENTRAL INDEX KEY:			0001370450
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-ENGINEERING SERVICES [8711]
		IRS NUMBER:				141951112
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		2401 EAST KATELLA AVENUE, SUITE 300
		CITY:			ANAHEIM
		STATE:			CA
		ZIP:			92806
		BUSINESS PHONE:		800-424-9144

	MAIL ADDRESS:	
		STREET 1:		2401 EAST KATELLA AVENUE, SUITE 300
		CITY:			ANAHEIM
		STATE:			CA
		ZIP:			92806
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>FORM 4 -
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2017-12-15</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001370450</issuerCik>
        <issuerName>Willdan Group, Inc.</issuerName>
        <issuerTradingSymbol>WLDN</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001452377</rptOwnerCik>
            <rptOwnerName>Chow Daniel</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2401 EAST KATELLA AVE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 300</rptOwnerStreet2>
            <rptOwnerCity>ANAHEIM</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>92806</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Operating Officer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2017-12-15</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>5</transactionFormType>
                <transactionCode>G</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value>E</value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>4000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>35131</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Includes (i) 6,667 shares of restricted stock that vest in two substantially equal installments on each of May 5, 2018 and May 5, 2019, (ii) 2,667 shares of restricted stock that vest in three substantially equal installments on each of March 8, 2018, March 8, 2019 and March 8, 2020 and (iii) 2,667 shares of restricted stock that vest in three substantially equal installments on each of October 31, 2018, October 31, 2019 and October 31, 2020.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Stacy McLaughlin, Attorney-in-fact for Daniel Chow</signatureName>
        <signatureDate>2017-12-19</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
