<SEC-DOCUMENT>0001179110-20-002788.txt : 20200303
<SEC-HEADER>0001179110-20-002788.hdr.sgml : 20200303
<ACCEPTANCE-DATETIME>20200303144446
ACCESSION NUMBER:		0001179110-20-002788
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20200229
FILED AS OF DATE:		20200303
DATE AS OF CHANGE:		20200303

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			KILLINGSTAD CHRIS
		CENTRAL INDEX KEY:			0001253755

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-16191
		FILM NUMBER:		20681509

	MAIL ADDRESS:	
		STREET 1:		C/O TENNANT COMPANY
		STREET 2:		701 N. LILAC DRIVE
		CITY:			MINNEAPOLIS
		STATE:			MN
		ZIP:			55422

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			TENNANT CO
		CENTRAL INDEX KEY:			0000097134
		STANDARD INDUSTRIAL CLASSIFICATION:	REFRIGERATION & SERVICE INDUSTRY MACHINERY [3580]
		IRS NUMBER:				410572550
		STATE OF INCORPORATION:			MN
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		701 N LILAC DR
		STREET 2:		PO BOX 1452
		CITY:			MINNEAPOLIS
		STATE:			MN
		ZIP:			55440
		BUSINESS PHONE:		7635401200

	MAIL ADDRESS:	
		STREET 1:		701 N LILAC DR
		STREET 2:		PO BOX 1452
		CITY:			MINNEAPOLIS
		STATE:			MN
		ZIP:			55440

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	TENNANT G H CO
		DATE OF NAME CHANGE:	19700515
</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>2020-02-29</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000097134</issuerCik>
        <issuerName>TENNANT CO</issuerName>
        <issuerTradingSymbol>TNC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001253755</rptOwnerCik>
            <rptOwnerName>KILLINGSTAD CHRIS</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>701 NORTH LILAC DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MINNEAPOLIS</rptOwnerCity>
            <rptOwnerState>MN</rptOwnerState>
            <rptOwnerZipCode>55422</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President and CEO</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2020-02-29</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>2921</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>71.54</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>164751</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3746.34</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By ESOP &amp; Profit Sharing</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes></footnotes>

    <ownerSignature>
        <signatureName>/s/ Kristin A. Stokes on behalf of Chris Killingstad</signatureName>
        <signatureDate>2020-03-03</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
