Osler’s Class Actions Defence Practice Group has successfully defended clients in many of the leading and complex class action cases in Canada. We specialize in developing multi-faceted national class action defence strategies and, when necessary, coordinating with U.S. counsel to supplement and execute a cohesive, solution-focused North American defence strategy.
We have an excellent track record in opposing and defeating class certification and winning early dismissals in every major jurisdiction in Canada. This practice includes mandates across a wide range of areas including product liability, consumer protection (Québec’s Consumer Protection Act), privacy, securities, environmental, false or misleading advertising, pensions and benefits, employment and franchise.

Canadian Class Action Defence Blog
We provide timely, reliable information about defending national and international class actions involving Canadian courts.
Our class action team is experienced in guiding clients through the most complex business-critical challenges. We offer:
- Risk mitigation – We work proactively with clients to develop risk management strategies to avoid claims whenever possible and to be “litigation ready” when claims are commenced. Osler will rapidly mobilize the right team to assist in minimizing the impact of a class action through immediate management of processes and documents, aggressive early assessment and planning, probable risk assessment, budget controls and crisis communications.
- National co-ordinating trial counsel – Our lawyers serve in the role of national counsel across Canada and are able to respond to cases simultaneously across the country, including in Québec, where civil rules apply. We have ongoing experience in leading and co-ordinating multijurisdictional, U.S. and international cases.
- Unmatched research capabilities – The research requirements for effective defence of a class action can be complex and detailed. Osler’s Research Department provides sophisticated support leading to precedent-setting results.
- Thought leadership – Our work has been instrumental in establishing leading principles of class action law, including the right of a defendant to defer the filing of a defence until after certification; the right to conduct examinations of representative plaintiffs in aid of certification; the nature of evidence to be filed on certification; the rules regarding solicitation of class members by plaintiff’s solicitors; and the necessity of considering the merits of the claim as part of the certification process.
- Discovery management – Our discovery management specialists have extensive experience in delivering customized, cost-effective and efficient discovery solutions in complex multijurisdictional class actions.
Key Contacts
Partner, Disputes, Toronto
Partner, Disputes, Vancouver
Partner, Disputes, Toronto
Partner, Disputes, Toronto
Partner, Disputes, Toronto
Partner, Disputes, Montréal
Representative Work
- Facebook Inc.
Facebook Inc. in the successful dismissal of the plaintiff’s appeal from an order denying certification of a proposed class action
- Facebook, Inc.
Facebook, Inc. in the successful dismissal of certification of a proposed class action
- BP p.l.c.
BP p.l.c. in Kaynes v BP
- Hydro One Inc.
Bennett v. Hydro One Inc. et al
- BP p.l.c.
BP p.l.c. in a securities class action arising from the 2010 Deepwater Horizon explosion
- GuestLogix Inc.
GuestLogix Inc. in proposed securities class action alleging misrepresentations contained in company’s public disclosures relating to certain credit facilities
- Manulife
Manulife in a proposed class action commenced in British Columbia relating to the distribution of mortgage insurance products by Manulife’s wholly-owned subsidiary, Benesure Canada Inc.
- Boston Scientific Ltd. and Boston Scientific Corporation
Boston Scientific Ltd. and Boston Scientific Corporation in fifteen individual matters in three provinces, as well as a certified class action in Ontario and three proposed class actions in other provinces (Saskatchewan, Alberta, Quebec)
- Facebook, Inc.
The BC Court of Appeal stayed a privacy class action in Douez v. Facebook, Inc. by enforcing a forum selection clause in favour of the courts of California. In a narrow 4-3 judgment, the SCC overturned the decision.
- Shoppers Drug Mart Corporation
Shoppers Drug Mart Inc. in a class action by pharmacist operators of Shoppers Drug Mart stores.
- Cadbury Adams Canada Inc. in 14 class actions across Canada arising from a regulatory investigation into the pricing and sale of chocolate confectionary products in Canada.
- Elpida Memory Inc. in an indirect purchaser class action related to alleged price fixing regarding DRAM.
- E.I. DuPont Canada Company in a class action involving pricing and distribution arrangements with independent distributors.
- Amex Bank of Canada in six class actions alleging various breaches of Québec’s Consumer Protection Act and constitutional challenges.
- Toronto-Dominion Bank in certification appeals and settlement of a class action seeking damages for fees applied to foreign exchange transactions on TD Visa credit cards.
- Vale Inco Limited in a class action on behalf of residents of the City of Port Colborne, alleging property damages related to historic emissions from Inco’s nickel refining activities.
- Vale Inco Limited in a class action arising from an accidental gas emission from one of the company’s facilities.
- Canada Mortgage and Housing Corporation in a class action relating to pension surplus.
- Hydro-Québec where a class action by retirees claiming pension surplus was dismissed.
- Michelin North America (Canada) Inc. in successfully resisting an appeal relating to contribution holidays and plan administration.
- Dell Canada Inc. in the Supreme Court of Canada on the ability of companies to oust the provincial class actions regime in favour of a commercial arbitration.
- Eli Lilly Canada Inc. and Eli Lilly & Company in defence of four proposed class actions in Ontario, Québec, British Columbia and Alberta on claims relating to alleged side effects of an antipsychotic drug.
- Imperial Tobacco in the successful defence of the largest proposed class action in Canada brought on behalf of all current and former smokers in Ontario.
- Microsoft Corporation n in a class action regarding billing practices for Internet access services provided by the Microsoft Network. The court upheld an exclusive jurisdiction clause in the “click wrap” licence agreement that each individual must accept before using the service.
- Procter and Gamble, whose branded pet food products were manufactured by Menu Foods Limited and distributed in Canada.
- State Farm Mutual Automobile Insurance Company in two separate proposed class actions relating to: (1) the use of non-original equipment manufactured parts in insured repairs; and (2) the applicability of an insured’s deductible when a vehicle is written off and salvaged.
Latest Insights
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Osler Update December 8, 2025
Québec’s Bill 10: new rules for subscriptions and ticket resale practices – what businesses need to know
The proposals would create a new legal framework for businesses in these sectors, amplifying risk in class action matters and regulatory scrutiny.
Read more -
Report December 4, 2025
Restructuring the Canadian tobacco industry: a model for the future?
The restructuring of the Canadian tobacco industry represented a unique path to the resolution of multiple claims in relation to tobacco-related...
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Blog October 30, 2025
Ontario court reaffirms that compensable loss is a ‘fundamental prerequisite’ to certification of a class action
The Court denied certification to a proposed class action, finding that such a proceeding was not the preferable procedure.
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Osler Update June 24, 2025
Private right of access for relief from anti-competitive harm now in force in Canada
The new right of access under the Competition Act represents the broadest expansion of private enforcement of Canada’s competition laws in a...
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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 Dispute Resolution: Class Action (Defense)
- One source says the firm is “great at high-level strategy. I’ve been impressed with the way they’ve been able to advocate seriously but also have a respectful relationship with co-defendants or counsel.”
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The Canadian Legal Lexpert Directory: Recognized in Class Actions (Toronto, Ontario; Montreal, Quebec)
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Benchmark Litigation Canada: Osler lawyers recognized in Class Action
In the Media
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Osler News November 20, 2025
24 Osler lawyers recognized in Lexpert Special Edition: Litigation 2025
Osler is proud to announce that 24 of our lawyers are recognized in the Lexpert Special Edition: Litigation 2025. This prestigious publication...
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Media Mentions October 8, 2025
Business litigators say Ontario’s proposal to shorten litigation dispute timelines is problematic – Canadian Lawyer
Recently proposed amendments to the Rules of Civil Procedure have prompted concern from lawyers in Ontario. In an effort to improve the provincial...
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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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Osler News May 2, 2025
Osler recognized for outstanding bench strength in the 2025 Benchmark Litigation Canada Guide
Osler is proud to announce that 31 of our lawyers have been recognized in the 2025 edition of the Benchmark Litigation Canada Guide, Benchmark’s...
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