<SEC-DOCUMENT>0000717538-18-000106.txt : 20180524
<SEC-HEADER>0000717538-18-000106.hdr.sgml : 20180524
<ACCEPTANCE-DATETIME>20180524091406
ACCESSION NUMBER:		0000717538-18-000106
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20180523
FILED AS OF DATE:		20180524
DATE AS OF CHANGE:		20180524

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			DeMarco David S.
		CENTRAL INDEX KEY:			0001463249

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-12507
		FILM NUMBER:		18856777

	MAIL ADDRESS:	
		STREET 1:		7 INGERSOL ROAD
		CITY:			SARATOGA SPRINGS
		STATE:			NY
		ZIP:			12866

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ARROW FINANCIAL CORP
		CENTRAL INDEX KEY:			0000717538
		STANDARD INDUSTRIAL CLASSIFICATION:	NATIONAL COMMERCIAL BANKS [6021]
		IRS NUMBER:				222448962
		STATE OF INCORPORATION:			NY
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		250 GLEN ST
		CITY:			GLENS FALLS
		STATE:			NY
		ZIP:			12801
		BUSINESS PHONE:		5184154299

	MAIL ADDRESS:	
		STREET 1:		250 GLEN STREET
		CITY:			GLENS FALLS
		STATE:			NY
		ZIP:			12801

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ARROW BANK CORP
		DATE OF NAME CHANGE:	19900710
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_152716763130995.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2018-05-23</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000717538</issuerCik>
        <issuerName>ARROW FINANCIAL CORP</issuerName>
        <issuerTradingSymbol>AROW</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001463249</rptOwnerCik>
            <rptOwnerName>DeMarco David S.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>7 INGERSOL ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SARATOGA SPRINGS</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>12866</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>SVP</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2018-05-23</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>4019</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>37.52</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>24185</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes></footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Thomas J. Murphy, Attorney in Fact</signatureName>
        <signatureDate>2018-05-24</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
