<SEC-DOCUMENT>0000034563-19-000071.txt : 20190917
<SEC-HEADER>0000034563-19-000071.hdr.sgml : 20190917
<ACCEPTANCE-DATETIME>20190917164856
ACCESSION NUMBER:		0000034563-19-000071
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20190913
FILED AS OF DATE:		20190917
DATE AS OF CHANGE:		20190917

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Maserang II D Deverl
		CENTRAL INDEX KEY:			0001543219

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-34249
		FILM NUMBER:		191097535

	MAIL ADDRESS:	
		STREET 1:		250 EAST FIFTH STREET
		CITY:			CINCINNATI
		STATE:			OH
		ZIP:			45202

	FORMER NAME:	
		FORMER CONFORMED NAME:	Maserang D Deverl
		DATE OF NAME CHANGE:	20120227

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			FARMER BROTHERS CO
		CENTRAL INDEX KEY:			0000034563
		STANDARD INDUSTRIAL CLASSIFICATION:	MISCELLANEOUS FOOD PREPARATIONS & KINDRED PRODUCTS [2090]
		IRS NUMBER:				950725980
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0630

	BUSINESS ADDRESS:	
		STREET 1:		1912 FARMER BROTHERS DRIVE
		CITY:			NORTHLAKE
		STATE:			TX
		ZIP:			76262
		BUSINESS PHONE:		888 998 2468

	MAIL ADDRESS:	
		STREET 1:		P O BOX 77057
		CITY:			FORT WORTH
		STATE:			TX
		ZIP:			76177
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_156875332013430.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2019-09-13</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000034563</issuerCik>
        <issuerName>FARMER BROTHERS CO</issuerName>
        <issuerTradingSymbol>FARM</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001543219</rptOwnerCik>
            <rptOwnerName>Maserang II D Deverl</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1912 FARMER BROTHERS DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NORTHLAKE</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>76262</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></nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>13.13</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2019-09-13</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>223713</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2026-09-13</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>223713.0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>223713</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The stock options will vest rateably over three years on each anniversary of the Transaction Date,  subject to the reporting person's continued employment with the Issuer through each vesting date.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Patrick Enunwaonye, Attorney-in-fact for D. Deverl Maserang, II</signatureName>
        <signatureDate>2019-09-17</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
