Osisko Development Announces Grant of Deferred Share Units

ODV NYSE TSXV News Release

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OSISKO DEVELOPMENT ANNOUNCES GRANT OF DEFERRED SHARE UNITS

Montreal, Québec, August 20, 202 5 – Osisko Development Corp. (NYSE: ODV, TSXV: ODV)

("Osisko Development" or the "Company") announces that it has granted 58,824 deferred share

units ("DSUs") of the Company to M s. Susan Craig, an independent director, as part of h er recent

appointment to the Company's board of directors announced on June 16, 2025.

The DSUs were granted in accordance with the Company's Omnibus Incentive Plan, which is available

on the Osisko Development website at www.osiskodev.com.

ABOUT OSISKO DEVELOPMENT CORP.

Osisko Development Corp. is a continental North American gold development company focused on past-

producing mining camps located in mining friendly jurisdictions with district scale potential. The

Company's objective is to become an intermediate gold produ cer by advancing its flagship permitted

100%-owned Cariboo Gold Project, located in central B.C., Canada. Its project pipeline is complemented

by the Tintic Project in the historic East Tintic mining district in Utah, U.S.A., and the San Antonio Gold

Project in Sonora, Mexico —brownfield properties with significant exploration potential, extensive

historical mining data, access to existing infrastructure and skilled labour. The Company's strategy is to

develop attractive, long-life, socially and environmenta lly responsible mining assets, while minimizing

exposure to development risk and growing mineral resources.

For further information, visit our website at www.osiskodev.com or contact:

Sean Roosen Philip Rabenok

Chairman and CEO Vice President, Investor Relations

Email: [email protected] Email: [email protected]

Tel: +1 (514) 940-0685 Tel: +1 (437) 423-3644

Neither the TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the

TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this news release. No stock exchange,

securities commission or other regulatory authority has approved or disapproved the information contained herein.