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UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington , D.C. 20549 Form 10 - K X ANNUAL REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31 , 2020 OR TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from Commission File Number 001-15149 LENNOX INTERNATIONAL INC . ( Exact name of Registrant as specified in its charter ) to Title of each class Common stock , $ 0.01 par value per share Delaware ( State or other jurisdiction of incorporation or organization ) ( I.R.S. Employer Identification Number ) 2140 Lake Park Blvd. Richardson , Texas 75080 ( Address of principal executive offices , including zip code ) ( Registrant's telephone number , including area code ) : ( 972 ) 497-5000 Securities Registered Pursuant to Section 12 ( b ) of the Act : Trading Symbol ( s ) 42-0991521 LII Name of each exchange on which registered New York Stock Exchange Securities Registered Pursuant to Section 12 ( g ) of the Act : None Indicate by checkmark if the registrant is a well - known seasoned issuer , as defined in Rule 405 of the Securities Act . Yes [ X ] No [ ] Indicate by checkmark if the registrant is not required to file reports pursuant to Section 13 or 15 ( d ) of the Exchange Act . Yes [ ] No [ X ] Indicate by check mark whether the registrant ( 1 ) has filed all reports required to be filed by Section 13 or 15 ( d ) of the Exchange Act during the preceding 12 months ( or for such shorter period that the registrant was required to file such reports ) , and ( 2 ) has been subject to such filing requirements for the last 90 days . Yes [ X ] No [ ] Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S - T ( §232.405 of this chapter ) during the preceding 12 months ( or for such shorter period that the registrant was required to submit such files ) . Yes [ X ] No [ ] Indicate by check mark whether the registrant is a large accelerated filer , an accelerated filer , a non - accelerated filer , a smaller reporting company , or an emerging growth company . See the definitions of “ large accelerated filer , " " accelerated filer , ” “ smaller reporting company , ” and “ emerging growth company " in Rule 12b - 2 of the Exchange Act . Large Accelerated Filer [ X ] [ ] Non - Accelerated Filer DOCUMENTS INCORPORATED BY REFERENCE Accelerated Filer Smaller Reporting Company Emerging Growth Company If an emerging growth company , indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13 ( a ) of the Exchange Act . [ ] [ ] Indicate by check mark whether the registrant has filed a report on and attestation to its management's assessment of the effectiveness of its internal control over financial reporting under Section 404 ( b ) of the Sarbanes - Oxley Act ( 15 U.S.C. 7262 ( b ) ) by the registered public accounting firm that prepared or issued its audit report Yes No Indicate by check mark whether the registrant is a shell company ( as defined in Rule 12b - 2 of the Exchange Act ) . Yes No X As of June 30 , 2020 , the aggregate market value of the common stock held by non - affiliates of the registrant was approximately $ 8.9 billion based on the closing price of the registrant's common stock on the New York Stock Exchange . As of February 5 , 2021 , there were 37,733,565 shares of the registrant's common stock outstanding . Portions of the registrant's 2020 Definitive Proxy Statement to be filed with the Securities and Exchange Commission in connection with the registrant's 2020 Annual Meeting of Stockholders to be held on May 20 , 2021 are incorporated by reference into Part III of this report .