<SEC-DOCUMENT>0001140361-18-008186.txt : 20180214
<SEC-HEADER>0001140361-18-008186.hdr.sgml : 20180214
<ACCEPTANCE-DATETIME>20180214163928
ACCESSION NUMBER:		0001140361-18-008186
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20180213
FILED AS OF DATE:		20180214
DATE AS OF CHANGE:		20180214

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			FREEMAN MICHAEL L
		CENTRAL INDEX KEY:			0001191593

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-06936
		FILM NUMBER:		18612506

	MAIL ADDRESS:	
		STREET 1:		405 SANDALWOOD COURT
		CITY:			ENCINITAS
		STATE:			CA
		ZIP:			92024

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			WD 40 CO
		CENTRAL INDEX KEY:			0000105132
		STANDARD INDUSTRIAL CLASSIFICATION:	MISCELLANEOUS CHEMICAL PRODUCTS [2890]
		IRS NUMBER:				951797918
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0831

	BUSINESS ADDRESS:	
		STREET 1:		9715 BUSINESSPARK AVENUE
		CITY:			SAN DIEGO
		STATE:			CA
		ZIP:			92131
		BUSINESS PHONE:		6192751400

	MAIL ADDRESS:	
		STREET 1:		9715 BUSINESSPARK AVENUE
		CITY:			SAN DIEGO
		STATE:			CA
		ZIP:			92131
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2018-02-13</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000105132</issuerCik>
        <issuerName>WD 40 CO</issuerName>
        <issuerTradingSymbol>WDFC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001191593</rptOwnerCik>
            <rptOwnerName>FREEMAN MICHAEL L</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>9715 CUDAHY PLACE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SAN DIEGO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>92131</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Strategy Officer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2018-02-13</value>
                <footnoteId id="F1"/>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>4861</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>119.58</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>24192.636</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Transaction pursuant to trading plan adopted pursuant to Rule 10b5-1 under Securities Exchange Act of 1934.</footnote>
        <footnote id="F2">Average price for multiple sales at prices ranging from $118.85 to $120.03 per share.</footnote>
        <footnote id="F3">Total includes 2,401.636 shares held in WD-40 Company Profit Sharing Plan (Company Stock Fund) account.  Also includes 5,539 Restricted Stock Units, of which 1,568 are subject to future vesting, 909 (target number) Market Share Units (MSUs) awarded to the reporting person in 2015, all of which are subject to future vesting, and 334 vested Deferred Performance Units (Common Stock equivalents). MSUs (which are performance-based equity awards) that were granted to the reporting person on October 11, 2016 and October 9, 2017 are not reported herein as beneficially owned Common Stock equivalents.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Richard T. Clampitt, attorney-in-fact for Michael L Freeman</signatureName>
        <signatureDate>2018-02-14</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
