Olivier is a partner in Osler’s National Tax Group based in Toronto and Montréal. His practice focuses on tax litigation and controversy, advising Canadian and international clients on complex tax audits and disputes both in and out of court.
As a litigator, he regularly appears before both the federal and Québec courts on tax matters, including at the appellate level.
A thought leader in Canadian tax law and former governor of the Canadian Tax Foundation, Oliver regularly contributes to the tax community through speaking and writing on significant tax issues. He was named a Lexpert Rising Star in 2020.
Prior to joining Osler, Olivier led the affiliated law firm of a national accounting firm as well as its national tax disputes practice.
Awards and Recognition
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Chambers Canada: Canada’s Leading Lawyers for Business: Recognized in Tax: Litigation
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Canadian Legal Lexpert Directory: Recognized in Litigation – Corporate Tax; Corporate Tax
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Lexpert Rising Star (2020)
Media Mentions
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Osler News May 4, 2026
Olivier Fournier joins Osler’s National Tax Group as a tax litigation partner
Olivier’s practice focuses on tax litigation and controversy, advising Canadian and international clients on complex tax audits and disputes both...
Read more
Credentials
Education
- University of Ottawa, LL.L.
- University of Ottawa, MBA
- University of Ottawa, B.Sc.
Languages
- English
- French
Professional Affiliations
- Barreau du Québec
- Law Society of Ontario
- Canadian Tax Foundation
- The Advocates’ Society
- Canadian Bar Association
- Association de planification fiscale et financière
