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

The undersigned, the President and Chief Executive Officer of Post Holdings, Inc. (the “Company”), hereby certifies, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that, to his knowledge on the date hereof:

(a)    the quarterly report on Form 10-Q for the period ended March 31, 2024, filed on the date hereof with the Securities and Exchange Commission (the “Report”), fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended; and

(b)    information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

Date:	May 3, 2024	By:	/s/ Robert V. Vitale
			Robert V. Vitale
			President and Chief Executive Officer

Certification Pursuant to

18 U.S.C. Section 1350, as adopted pursuant to

Section 906 of the Sarbanes-Oxley Act of 2002

The undersigned, the Senior Vice President, Chief Financial Officer and Treasurer of Post Holdings, Inc. (the “Company”), hereby certifies, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that, to his knowledge on the date hereof:

(a)    the quarterly report on Form 10-Q for the period ended March 31, 2024, filed on the date hereof with the Securities and Exchange Commission (the “Report”), fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended; and

(b)    information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

Date:	May 3, 2024	By:	/s/ Matthew J. Mainer
			Matthew J. Mainer
			Senior Vice President, Chief Financial Officer and Treasurer