Exhibit 32.1

CERTIFICATION OF CHIEF EXECUTIVE OFFICER AND CHIEF FINANCIAL OFFICER

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 Annual Report on Form 10-K of Annexon, Inc. (the “Company”) for the year ended December 31, 2020 (the “Report”) filed with the Securities and Exchange Commission on the date hereof, Douglas Love, President and Chief Executive Officer of the Company, and  Jennifer Lew, Executive Vice President and Chief Financial Officer of the Company, each hereby certifies, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that:

1. The Report fully complies with the requirements of Section 13(a) or Section 15(d) of the Securities Exchange Act of 1934, as amended; and

2. The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

Date: March 25, 2021	/s/ Douglas Love
	Douglas Love, Esq.
	President and Chief Executive Officer (Principal Executive Officer)
Date: March 25, 2021	/s/ Jennifer Lew
	Jennifer Lew
	Executive Vice President and Chief Financial Officer (Principal Financial and Accounting Officer)