UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13a-16 OR 15d-16 OF THE SECURITIES EXCHANGE ACT OF 1934

For the month of March 2024

Commission File Number: 001-38064

Aeterna Zentaris Inc.

(Translation of registrant’s name into English)

c/o Norton Rose Fulbright Canada, LLP, 222 Bay Street, Suite 3000, PO Box 53, Toronto ON M5K 1E7

(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

Form 20-F ☒ Form 40-F ☐

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1):

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7):

On March 26, 2024, the registrant filed in Canada its consolidated financial statements and Management’s Discussion and Analysis as of December 31, 2023 and 2022 and for the years ended December 31, 2023, 2022 and 2021, with the Canadian Securities Administration.

DOCUMENTS INDEX

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.