SEC Form 6-K filed by Quantum Biopharma Ltd.

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 October 2025

Commission File Number: 001-39152

QUANTUM BIOPHARMA LTD.

(Registrant)

1 Adelaide Street East, Suite 801

Toronto, Ontario M5C 2V9

(Address of Principal Executive Offices)

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):  ☐

DOCUMENTS INCORPORATED BY REFERENCE

Exhibits 99.3 through 99.11 of this Form 6-K are hereby incorporated by reference into the Registrant’s Registration Statement on Form F-3 (File No. 333-276264) and shall be deemed to be a part thereof from the date on which this report is furnished, to the extent not superseded by documents or reports subsequently filed or furnished.

SIGNATURES

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.

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