DENISON MINES CORP.

The Company has adopted a code of ethics that applies to the Company’s directors, officers and employees, including the Chief Executive Officer, the Chief Financial Officer, the principal accounting officer or controller, persons performing similar functions and other officers, directors and employees of the Company. A current copy of the code of ethics is on the Company’s website at www.denisonmines.com. In the fiscal year ended December 31, 2023, the Company has not made any amendment to a provision of its code of ethics that applies to any of its Chief Executive Officer, Chief Financial Officer, principal accounting officer or controller or persons performing similar functions that relates to one or more of the items set forth in paragraph (9)(b) of General Instruction B to Form 40-F. In the fiscal year ended December 31, 2023, the Company has not granted a waiver (including an implicit waiver) from a provision of its code of ethics to any of its Chief Executive Officer, Chief Financial Officer, principal accounting officer or controller or persons performing similar functions that relates to one or more of the items set forth in paragraph (9)(b) of General Instruction B to Form 40-F.