<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-11-03</periodOfReport>

    <issuer>
        <issuerCik>0000737758</issuerCik>
        <issuerName>TORO CO</issuerName>
        <issuerTradingSymbol>TTC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001201729</rptOwnerCik>
            <rptOwnerName>STEINHAFEL GREGG W</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>8111 LYNDALE AVENUE SOUTH</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BLOOMINGTON</rptOwnerCity>
            <rptOwnerState>MN</rptOwnerState>
            <rptOwnerZipCode>55420-1196</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-11-03</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>534</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>26061</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock Units</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1225.546</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>33.78</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2008-11-03</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F3"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>3337</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2009-11-03</value>
                <footnoteId id="F4"/>
            </exerciseDate>
            <expirationDate>
                <value>2018-11-03</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>3337</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3337</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F4">The option vests in three equal annual installments commencing in the year following the date of grant.</footnote>
        <footnote id="F1">Annual Common Stock award for service as a director issued under The Toro Company 2000 Directors Stock Plan.</footnote>
        <footnote id="F2">Includes the following Common Stock Units acquired by the reporting person under the dividend reinvestment feature of The Toro Company Deferred Compensation Plan for Non-Employee Directors:  3.848 Common Stock Units on January 11, 2008; 4.368 Common Stock Units on April 11, 2008; 5.997 Common Stock Units on July 11, 2008; and 5.652 Common Stock Units on October 17, 2008.  Also includes an account adjustment of .0105 Common Stock Units.</footnote>
        <footnote id="F3">Annual stock option grant for service as a director issued under The Toro Company 2000 Directors Stock Plan.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Stacy L. Bogart, Atty-In-Fact</signatureName>
        <signatureDate>2008-11-05</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0303
4
2008-11-03
0000737758
TORO CO
TTC
0001201729
STEINHAFEL GREGG W
8111 LYNDALE AVENUE SOUTH
BLOOMINGTON
MN
55420-1196
1
0
0
0
Common Stock
2008-11-03
4
A
0
534
0
A
26061
D
Common Stock Units
1225.546
D
Stock Option
33.78
2008-11-03
4
A
0
3337
0
A
2009-11-03
2018-11-03
Common Stock
3337
3337
D
The option vests in three equal annual installments commencing in the year following the date of grant.
Annual Common Stock award for service as a director issued under The Toro Company 2000 Directors Stock Plan.
Includes the following Common Stock Units acquired by the reporting person under the dividend reinvestment feature of The Toro Company Deferred Compensation Plan for Non-Employee Directors:  3.848 Common Stock Units on January 11, 2008; 4.368 Common Stock Units on April 11, 2008; 5.997 Common Stock Units on July 11, 2008; and 5.652 Common Stock Units on October 17, 2008.  Also includes an account adjustment of .0105 Common Stock Units.
Annual stock option grant for service as a director issued under The Toro Company 2000 Directors Stock Plan.
Stacy L. Bogart, Atty-In-Fact
2008-11-05