Exhibit 32.1

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350

AS ADOPTED PURSUANT TO SECTION 906

OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report on Form 10-Q of Blue Buffalo Pet Products, Inc. (the “Company”) for the quarterly period ended June 30, 2015 filed with the Securities and Exchange Commission on the date hereof (the “Report”), we, the undersigned officers of the Company, do hereby certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that:

• The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

• The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company for the periods presented therein.

Date: August 14, 2015

/s/ Kurt Schmidt    Kurt Schmidt
Chief Executive Officer
(Principal Executive Officer)

/s/ Michael Nathenson    

Michael Nathenson

Executive Vice President, Chief Financial Officer, and Treasurer

(Principal Finance and Accounting Officer)