Osisko Development Corp. — Capital/Financing Update 2025

Dec 23, 2025

Bennett Jones

Bennett Jones LLP
3400 One First Canadian Place, PO Box 130
Toronto, Ontario, Canada M5X 1A4
Tel: 416.863.1200 Fax: 416.863.1716

December 23, 2025

VIA SEDAR+

Autorité des marchés financiers (Québec)
British Columbia Securities Commission
Alberta Securities Commission
Financial and Consumer Affairs Authority of Saskatchewan
The Manitoba Securities Commission
Ontario Securities Commission
Financial and Consumer Services Commission, New Brunswick
Nova Scotia Securities Commission
Superintendent of Securities, Prince Edward Island
Superintendent of Securities, Newfoundland and Labrador
Superintendent of Securities, Northwest Territories
Superintendent of Securities, Nunavut
Yukon Superintendent of Securities

Re: Osisko Development Corp.

Dear Sirs/Mesdames:

We refer to the final short form base shelf prospectus of Osisko Development Corp. (the "Corporation") dated December 23, 2025 (the "Prospectus") in connection with the qualification for the distribution by the Corporation, from time to time, to purchasers in each of the provinces and territories of Canada of up to an aggregate offering price $750,000,000 (or the equivalent in other currencies or currency units based on the applicable exchange rate at the time of the offering) of common shares in the capital of the Corporation ("Common Shares"), debt securities which may consist of bonds, debentures, notes or other evidences of indebtedness of any kind, nature or description and which may be issuable in series ("Debt Securities"), subscription receipts convertible to Common Shares or other Securities ("Subscription Receipts"), warrants to purchase Common Shares and other Securities ("Warrants"), and units comprised of one or more of any of the other Securities or any combination of such Securities ("Units"), or any combination of such securities (all of the foregoing collectively with the Common Shares, Debt Securities, Subscription Receipts and Warrants, the "Securities").

We hereby consent to the references to our firm name in the Prospectus under the headings "Documents Filed as Part of the Registration Statement", "Enforcement of Judgements", "Enforceability of Civil Liabilities" and "Legal Matters".

We confirm that we have read the Prospectus and have no reason to believe that there are any misrepresentations in the information contained in the Prospectus that are within our knowledge as a result of the services we performed in connection with such matters.

Yours truly,

(signed) "Bennett Jones LLP"

Bennett Jones LLP

www.bennettjones.com