Guy Pratte
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Guy J. Pratte

Senior Counsel

Ottawa
Toronto
Montréal
[email protected]
613.787.3521  416.350.2638  514.954.2545
416.700.6265

Expertise

Michelle Volpe

Practice Assistant

Montréal
[email protected]
514.954.1905
514.954.2555

Shania Campbell

Practice Assistant

Toronto
[email protected]
416.367.6523

An award-winning and highly sought-after lawyer, Guy has experience in complex commercial litigation (including class actions), administrative law and constitutional law cases.

Guy frequently appears before the Supreme Court of Canada (SCC), the Superior and Appeal Courts of Ontario and Québec, the Federal Court (FC) and Federal Court of Appeal (FCA).

Guy was named to the Order of Canada in 2022, recognizing his contributions as a lawyer, notably to pro bono work, and for his volunteer commitments to the performing arts.

Testimonials

Who's Who Legal

"He's outstanding. A hard-working and dynamic practitioner who receives praise for always adding value for his clients."

"Guy Pratte is known for his solutions-oriented approach and is considered a leading trial lawyer."

Chambers Global

"He is singled out for the depth of his experience and is considered to be at the top of his field by his peers He’s always included in major cases."

“Guy Pratte is lauded for his proficiency in commercial litigation and his involvement in high-stakes class actions. He stands out for his strong track record before both the Ontario and Québec courts, as well as before the Supreme Court of Canada.” Sources say he “has a stellar reputation" as "one of the finest lawyers in the country."

Canadian Lawyer Magazine

"One of the best civil litigators in the country."

National Post

"A most principled man."

Benchmark Canada

"Guy is one of the best lawyers in Canada and has been excellent as lead counsel on all of our matters. He has the trust of the upper management and the respect from all courts."

Experience

  • York University v. Canadian Copyright Licensing Agency (to be heard in May 2021)
  • Grant Thornton LLP v. Province of New Brunswick (heard in March 2021 and judgment reserved)
  • Reference re Greenhouse Gas Pollution Pricing Act, 2021 SCC 11
  • 362222 Canada inc. v. Prelco inc. (heard in December 2020 and judgment reserved)
  • Conférence des juges de la Cour du Québec v. Chief Justice (heard in September 2020 and judgment reserved)
  • Nova Scotia (Attorney General) v. Judges of the Provincial Court and Family Court of Nova Scotia, 2020 SCC 21 (appeal allowed in part)
  • Volkswagen Group Canada Inc. v. Association québécoise de lutte contre la pollution atmosphérique, 2019 SCC 53 (appeal dismissed)
  • Trinity Western University c. Law Society of Upper Canada, 2018 CSC 33, [2018] 2 R.C.S. 453 (appeal dismissed)
  • Deloitte & Touche v. Livent Inc. (Receiver of), 2017 SCC 63 (appeal allowed in part)
  • World Bank Group v. Wallace, 2016 SCC 15, [2016] 1 S.C.R. 207 (appeal allowed)
  • Canadian Pacific Railway Co. v. Canada (Attorney General), 2016 SCC 1, [2016] 1 S.C.R. 6 (appeal dismissed)
  • Hinse v. Canada (Attorney General), 2015 SCC 35, [2015] 2 S.C.R. 621 (appeal dismissed);
  • Canadian National Railway Co. v. Canada (Attorney General), 2014 SCC 40, [2014] 2 S.C.R. 135 (appeal dismissed)
  • Québec (Attorney General) v. A, 2013 SCC 5, [2013] 1 S.C.R. 61, 2013 CSC 5, [2013] 1 R.C.S. 61 (appeal allowed)
  • Cinar Corporation v. Robinson, 2013 SCC 73, [2013] 3 S.C.R. 1168 (appeal dismissed)
  • S.L. v. Commission scolaire des Chênes, 2012 SCC 7, [2012] 1 S.C.R. 235 (appeal dismissed)
  • Canada (Attorney General) v. PHS Community Services Society, 2011 SCC 44, [2011] 3 S.C.R. 134, 2011 CSC 44, [2011] 3 R.C.S. 134 (appeal dismissed)
  • Bou Malhab v. Diffusion Métromédia CMR inc., 2011 SCC 9, [2011] 1 S.C.R. 214 (appeal dismissed)
  • Ontario (Public Safety and Security) v. Criminal Lawyers’ Association, 2010 SCC 23, [2010] 1 S.C.R. 815 (appeal allowed)
  • Canadian National Railway Co. v. Royal and Sun Alliance Insurance Co. of Canada, [2008] 3 S.C.R. 453, 2008 SCC 66 (appeal allowed)
  • Chaoulli v. Québec (Attorney General), [2005] 1 S.C.R. 791, 2005 SCC 35 (appeal allowed)
  • Finney v. Barreau du Québec, [2004] 2 S.C.R. 17, 2004 SCC 36 (appeal allowed)
  • Reference re Bill 30, An Act to Amend the Education Act (Ont.), [1987] 1 S.C.R. 1148 (appeal dismissed)
  • Trinity Western University v. Law Society of Upper Canada (under reserve), November/December 2017)
  • Deloitte & Touche v. Livent Inc., 2017 SCC 36875
  • World Bank Group v. Wallace, 2016 SCC 15
  • Canadian National Railway Co. v. Canada (Attorney General), 2014 SCC 40
  • Hinse v. Canada (Attorney General), 2013 S.C.C.A. 448
  • Québec (Attorney General) v. A., 2013 SCC 5
  • Cinar Corporation v. Robinson, 2013 SCC 73
  • S.L. v. Commission scolaire des Chênes, 2012 SCC 7
  • Canada (Attorney General) v. PHS Community Services Society, 2011 SCC 44
  • Bou Malhab v. Diffusion Métromédia CMR Inc., 2011 SCC 9
  • Ontario (Public Safety and Security) v. Criminal Lawyers’ Association, 2010 SCC 23
  • Canadian National Railway Co. v. Royal and Sun Alliance Insurance Co. of Canada, 2008 SCC 66
  • Chaoulli v. Québec (Attorney General), 2005 SCC 35
  • Finney v. Barreau du Québec, 2004 SCC 36
  • Lead counsel for Canadian National Railway Co. in an appeal against Richardson International Ltd. before the FCA
  • Lead counsel for the Board of Internal Economy and The Honourable Andrew Scheer (speaker of the House of Commons) in several judicial review applications commenced by the NDP in the FC
  • Lead counsel for the Law Society of Upper Canada in a judicial review application commenced by Trinity Western University in the Ontario Divisional Court
  • Commissioner of Official Languages of Canada v. CBC/Radio-Canada, 2014 FC 849
  • McCracken v. Canadian National Railway Co., 2012 ONCA (Ontario Court of Appeal) 445 (class certification reversed on appeal)
  • Pelletier v. Canada (Attorney General), 2008 FC 803
  • Independent counsel for the Canadian Judicial Council in the matter of certain allegations made against ACJ Douglas of the Manitoba Court of Queen’s Bench, 2011-2012
  • Lead counsel for the Right Honourable Brian Mulroney before the Oliphant Commission of Inquiry, 2008-2010
  • Lead counsel for Mr. Jean Pelletier (former chief of staff to the Right Honourable Prime Minister of Canada Jean Chrétien) before the Commission of Inquiry into the Sponsorship Program and Advertising Activities before the Federal Court and Federal Court of Appeal
  • Lead counsel for JTI-MacDonald and RJR Tobacco Companies in ongoing healthcare cost recovery actions brought by the Governments of Ontario (C$50B) and Québec (C$60B)
  • Lead counsel for JTI MacDonald in ongoing tobacco-related class actions in the province of Québec (C$20B)

Beyond Our Walls

Professional Involvement

  • President, The Advocates' Society (2020-2021)
  • Treasurer, The Advocates' Society (2018-2019)
  • Secretary, The Advocates' Society (2017-2018)
  • Director, The Advocates' Society (2014-present)
  • Chair, Pro Bono Ontario (2016-2019)
  • Director, Pro Bono Ontario (2016-2019)
  • Founder and former president, Pro Bono Québec (2008-2011)
  • President, Beverly McLachlin Access to Justice Award Committee (2019-2020)
  • Fellow, American College of Trial Lawyers (2007-present)
  • Members, Access to Justice Committee, American College of Trial Lawyers (2010- present)
  • Co-chair, Access to Justice Committee, American College of Trial Lawyers (2010- 2013)
  • Director and Vice-Chair, Supreme Court Advocacy Institute (2009)
  • Director and Officer, Canadian Institute for Advanced Legal Studies (2008-present)
  • Director, County of Carleton Law Association (1998-1999)
  • President, Association des juristes d’expression française de l’Ontario (1993-1994)
  • Guest Lecturer (Good Judgment: The Role of an Appellate Judge), University of Toronto Law School (2019, 2020, 2021)
  • Adjunct professor, “The Supreme Court of Canada in Search of Justice,” University of Toronto Law School (2012, 2014, 2017)
  • Guest Lecturer (Appellate Advocacy), McGill University (2018/2020)
  • Holder of the Milvain Chair in Advocacy, University of Calgary Law School (2013)
  • Guest Lecturer, “A Virtual Tour of the Modern Practice of Law,” University of Western Ontario (2001)
  • Part-time Professor (Law of Evidence), University of Ottawa, Faculty of Common Law (1990-1994)
  • Instructor (Administrative Law), Law Society of Upper Canada, Bar Course (1990s)

Community Involvement

  • Chair, National Arts Centre Foundation (2003-2010)
  • Member, Board of Governors, Stratford Festival of Canada (2011-2018)
  • Director, Board of Directors, Centre for Addiction and Mental Health (2013)

Awards & Recognitions

  • Recognized in the 2025 (and since 2016) editions of Chambers Canada — Canada's Leading Lawyers for Business (Litigation: Administrative & Public Law, Litigation: General Commercial; Dispute Resolution)
  • Selected by peers for inclusion in the 2025 edition (and since 2006) of The Best Lawyers in Canada® (Administrative and Public Law; Appellate Practice; Class Action Litigation; Corporate and Commercial Litigation), (and in 2021) of Best Lawyers in Canada as "Lawyer of the Year" (Administrative and Public Law, Appellate Advocacy) and in 2025 (since 2022) (Railroad Law)
  • Recognized in the 2024 edition of Lexpert Special Edition: Energy and Mining
  • Recognized in the 2024 edition (and since 2023) of The Lexpert/American Lawyer Guide to the Leading 500 Lawyers in Canada (Litigation - Corporate Commercial)
  • Recognized in the 2024 edition (and since 2013) of The Canadian Legal Lexpert® Directory (Litigation: Corporate Commercial; Litigation: Public Law; Litigation: Directors' and Officers' Liability; Class Actions; Litigation: Defamation & Media; Energy: Electricity; Energy: Oil and Gas)
  • Recognized in the 2023 edition (and since 2020) of Lexpert Special Edition: Litigation
  • Recognized in the 2023 edition (and since 2013) of Chambers Global – The World’s Leading Lawyers for Business (Dispute Resolution: Litigation)
  • Recognized in the 2023 edition (and since 2022) of the Legal 500 Canada as a "Leading Lawyer" (Disputes Resolution)
  • Recognized in the 2024 edition (and since 2023) of Who's Who Legal: Canada (Commercial Litigation).
  • Recognized as a leading energy lawyer in the 2013-2018 and 2020-2023 editions of the Lexpert® Special Edition — Canada’s Leading Energy Lawyers
  • Consistently recognized in The Best Lawyers in Canada as Ottawa Administrative and Public Law - Lawyer of the Year and Ottawa Appellate Practice - Lawyer of the Year
  • Recognized in the 2021 edition of Benchmark Canada – The Definitive Guide to Canada’s Leading Litigation Firms & Attorneys as a Local Litigation Star: Toronto and Ottawa
  • Received the Ontario Bar Association Award for Excellence in Civil Litigation in 2019
  • Received the Law Society of Ontario Medal in 2019
  • Received the Barreau de Montréal Medal in 2018
  • Recognized in the 2018 edition (and since 2013) of The Lexpert®/American Lawyer Guide to the Leading 500 Lawyers in Canada (Litigation: Corporate Commercial)
  • Recognized in the 2018 edition (and since 2014) of Legal 500 Canada (Dispute Resolution)
  • Recognized in the 2018 edition (and since 2013) of Benchmark Canada — The Definitive Guide to Canada's Leading Litigation Firms and Attorneys as one of the top 50 trial lawyers in Canada (Class Action: Constitutional; General Commercial)
  • Recognized by the 2018 Benchmark Canada Awards — hall of fame lawyer of the year
  • Awarded the prestigious St. Yves Medal by Pro bono Québec in 2014
  • Recognized with a Lexpert® Zenith Award (pro bono team of the year — firm) in 2011 for the Réjean Hinse wrongful conviction civil lawsuit
  • Received the Advocatus Emeritus Award, Association du Barreau du Québec in 2012

Bar Admission & Education

  • Ontario, 1984
  • Québec, 2002
  • LLB, University of Toronto
  • MA (philosophy), University of Toronto
  • BA (Hons., Gold Medallist, history and philosophy), University of Western Ontario