<SEC-DOCUMENT>0001179110-21-005137.txt : 20210511
<SEC-HEADER>0001179110-21-005137.hdr.sgml : 20210511
<ACCEPTANCE-DATETIME>20210511135703
ACCESSION NUMBER:		0001179110-21-005137
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20210510
FILED AS OF DATE:		20210511
DATE AS OF CHANGE:		20210511

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Huml David W.
		CENTRAL INDEX KEY:			0001624242

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-16191
		FILM NUMBER:		21910703

	MAIL ADDRESS:	
		STREET 1:		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:		104000 CLEAN STREET
		CITY:			EDEN PRAIRIE
		STATE:			MN
		ZIP:			55344
		BUSINESS PHONE:		7635401200

	MAIL ADDRESS:	
		STREET 1:		104000 CLEAN STREET
		CITY:			EDEN PRAIRIE
		STATE:			MN
		ZIP:			55344

	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>2021-05-10</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001624242</rptOwnerCik>
            <rptOwnerName>Huml David W.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>10400 CLEAN STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>EDEN PRAIRIE</rptOwnerCity>
            <rptOwnerState>MN</rptOwnerState>
            <rptOwnerZipCode>55344</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>2021-05-10</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1063</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>85.2346</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>23786</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2021-05-10</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>3932</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>86.6158</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>19854</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Reflects the weighted average price of 1,063 shares of common stock of Tennant Company sold by the reporting person in multiple transactions on May 10, 2021 with sale prices ranging from $85.08 to $86.05 per share. The reporting person undertakes to provide upon request by the U.S. Securities and Exchange Commission staff, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.</footnote>
        <footnote id="F2">Reflects the weighted average price of 3,932 shares of common stock of Tennant Company sold by the reporting person in multiple transactions on May 10, 2021 with sale prices ranging from $86.13 to $86.70 per share. The reporting person undertakes to provide upon request by the U.S. Securities and Exchange Commission staff, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Kristen A. Stokes on behalf of David W. Huml</signatureName>
        <signatureDate>2021-05-11</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
