Osler’s disputes practice is one of the largest and most accomplished in Canada. Years of careful recruiting and rigorous training have allowed us to develop deep expertise in complex corporate and commercial litigation.
As experienced trial and appeal lawyers, our litigators appear as counsel in all levels of courts in Ontario, Alberta, Québec and most other Canadian provinces, as well as in the Federal Court and the Supreme Court of Canada. We also participate regularly in hearings before a variety of provincial and federal tribunals, including: the Financial Services Tribunal, the Ontario Municipal Board, the Environmental Assessment Board, the Ontario Securities Commission, and the Autorité des Marchés Financiers (AMF).
In addition to our trial expertise, we assist clients in identifying and mitigating risks that could lead to new legal exposures. We focus on developing a deep knowledge of each client’s business, which enables us to intervene effectively to avoid lengthy proceedings or to achieve cost-effective and innovative solutions through early prevention or alternative dispute resolution. Our discovery management specialists work strategically with our litigators and clients to deliver an array of customized, cost-effective and efficient discovery solutions. In short, Osler is home to a critical mass of top litigators in their respective fields — with the track records and the loyal and growing client base to prove it.
Ask us about:
- Appeals
- Class Actions
- Competition/Antitrust Litigation
- Constitutional and Public Law
- Construction and Infrastructure Litigation
- Corporate Governance and Securities Litigation
- Cross-Border Litigation
- Defamation (Libel and Slander)
- Discovery Management
- Energy and Natural Resources Litigation
- Environmental Litigation
- Franchise Litigation
- Insolvency and Restructuring
- Intellectual Property Litigation
- International Commercial Arbitration and ADR
- Municipal Litigation
- Pensions and Benefits Litigation
- Product Liability
- Professional Negligence
- Tax Dispute Resolution
Key Contacts
Partner, Disputes, Toronto
Partner, Disputes, Vancouver
Partner, Disputes, Toronto
Partner, Disputes, Montréal
Latest Insights
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Video January 9, 2024
Business considerations in litigation
When faced with a dispute, businesses must weigh a variety of factors to know what action to take. If you receive a claim, or think you have a claim...
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Osler Update July 14, 2025
Artificial advocacy: how Canadian courts and legislators are responding to generative AI
With Canadian courts responding to the use of AI in court filings in a number of ways, litigants must balance using AI with their duties to the court.
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Blog May 28, 2025
Abuse of process: the continuing saga of Morabito
The B.C. Court of Appeal has found a blended hearing of an abuse of process claim and an insider trading claim to be “fundamentally flawed”.
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Blog March 18, 2025
Further updates regarding the U.S. pro-crypto policy shift
A clear shift in U.S. crypto priorities suggests substantial change, potentially leading to regulatory clarity and crypto-specific legislation.
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Stay up to date with our latest insights
SubscribeAwards and Recognition
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Chambers Canada: Canada’s Leading Lawyers for Business: Recognized in Litigation: General Commercial (Nationwide; Ontario; Alberta; Quebec)
- “They really understand the business and they are extremely responsive. They don’t try and over-lawyer files and their answers are always practical.”
- “They have good bench strength and have really taken the time to learn our business. They are bright, hard-working individuals.”
- “They are excellent and I have really enjoyed working with them. They have some really great young talent.”
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The Canadian Legal Lexpert Directory: Recognized in Corporate Commercial Litigation (Toronto, Ontario; Montréal, Québec; Calgary, Alberta); Professional Liability (Toronto, Ontario)
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Legal 500: Recognized in Dispute Resolution (Alberta; Ontario; Québec)
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Benchmark Litigation Canada: Recognized in Dispute Resolution (Ontario, Québec, Alberta); Osler lawyers recognized in Litigation and Dispute Resolution
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Best Lawyers Canada: Recognized as “Law Firm of the Year” in the area of Corporate and Commercial Litigation (Canada), 2022
In the Media
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Osler News June 10, 2025
Keith Marlowe, KC, joins Osler’s Disputes group as a partner
Keith is a veteran litigator whose broad practice focuses on corporate and commercial disputes, including cross-border disputes and class actions.
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Media Mentions May 20, 2025
OBA launches portal to help lawyers find pro bono work – Canadian Lawyer
Systematizing the delivery of pro bono services is essential to bridging the gap between demand and supply, says partner Mary Paterson, Disputes, in...
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Media Mentions May 16, 2025
Alberta court confirms CCAA power to release directors from excise tax liability – LAW360
The recent decision of the Alberta Court of King’s Bench to release corporate directors from personal liability for unpaid excise taxes was a...
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Osler News May 9, 2025
Maureen Killoran, KC, named Energy/Resources Litigator of the Year at the 2025 Benchmark Canada Awards
National Co-Chair Maureen Killoran, KC, has once again been named the Energy/Resources Litigator of the Year.
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