Expertise
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Practice Areas:
- Bar Admissions:
- Education:
- University of Toronto (2009) LLM
- University of Toronto (2003) LLB (Honours Standing - 3rd Year)
- University of Toronto (1999) MA (English Literature)
- McGill University (1998) BA (Honours - English Literature)
Details
- Bio
- Cases
- Associations
- Blog Posts
- News & Media
- Publications & Presentations
- Recognition
Jaan Lilles
is a partner at Lenczner Slaght and the head of the firm’s Professional Liability practice group.
"Jaan handles all matters, no matter the complexity, and takes on every challenge with the same even-keeled approach. His recommendations are direct and to the point. He has achieved excellent outcomes for his clients despite challenging facts." — Chambers Canada
Jaan’s practice includes a diverse range of litigation: professional liability, medical malpractice, commercial disputes, employment, and administrative law. He has appeared before all levels of court in Ontario, including as lead counsel in the Court of Appeal for Ontario, Divisional Court and the Ontario Superior Court of Justice and he has appeared in the Supreme Court of Canada.
Jaan regularly represents clients before administrative tribunals both as a prosecutor and as defence counsel. He has handled professional discipline matters before the Law Society Tribunal and several Discipline Committees of various regulated health colleges. He has frequently participated in judicial review applications and appeals from administrative tribunals.
A keen interest in the legal theory of privacy led Jaan to pursue a Master's of Law degree at the University of Toronto, where his graduate thesis was titled "The Common Law Right to Privacy." Jaan is a regular speaker at continuing legal education events and taught for three years as an adjunct professor at the Faculty of Law, Western University.
Jaan has been recognized as a leading lawyer by various organizations including Lexpert, Best Lawyers, and Benchmark Canada.
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Mukankubana v Toronto East General Hospital
Counsel to the defendant obstetrics and gynecology physicians in a medical negligence action in respect of a complex delivery and post-delivery injuries. Successfully obtained summary judgment dismissing the action against all defendant physicians.
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Counsel to the successful respondent physician in a complaint before the Information and Privacy Commissioner of Ontario, relating to the application of the access provisions of the Personal Health Information Protection Act in a circumstance where the complainant was a relative and not a patient.
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Chief James Marlowe and the Lutsel K’e Dene First Nation v Mirza Mohammad Imran Karim Barlas et al
Counsel to the Lutsel K’e Dene First Nation and its elected chief in an oppression application (and related injunction) arising from allegations of breach of fiduciary duty, misappropriation, and fraud by the CEO of the First Nations’ company.
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Counsel to a physician in rare medical malpractice case before the Supreme Court of Canada, which discussed interesting issues relating to the standard of care.
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Counsel to a successful defendant in an ANTI-SLAPP motion arising out of statements made during the COVID-19 pandemic. The case involved interesting issues of the limits of free speech and alleged misinformation in the context of a global pandemic. The matter received significant media attention.
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Counsel to a physician on a motion to determine the existence of a novel duty of care in the health care setting.
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Counsel to the successful defendant physician in the trial of an action involving a bowel perforation in a laparoscopic hysterectomy.
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College of Traditional Chinese Medicine Practitioners and Acupuncturists of Ontario v Xu
Counsel to the College of Traditional Chinese Medicine Practitioners in a complex prosecution of a member found guilty of issuing false diplomas to numerous applicants to the College. The matter raised issues of fundamental importance to the College including the integrity of its registration system.
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Law Society of Ontario v Sorrenti
Counsel to the Law Society of Ontario in an application to have a trustee appointed over a Lawyer’s mortgage administration practice.
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Counsel to the Plaintiff in copyright case on a novel motion to impose a discovery plan.
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Ontario Bar Association
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The Advocates' Society
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Canadian Bar Association
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University of Western Ontario, Faculty of Law - Past Adjunct Professor (2014-2016)
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Entire agreement clauses: usually, but not always, the entire story
Entire agreement clauses are often used to insulate contracting parties from disputes over pre-contractual representations. The recent decision of Curtis Chandler v Karl Hollett demonstrates how bare allegations of pre-contractual misrepresentation will rarely win out over such clauses.
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Participant Experts: who are they, and what can they say?
Expert witnesses have an obligation to be independent and impartial, but not all expert witnesses are created equal.
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Québec Court of Appeal Affirms Duty to Protect and Enhance Brand
The Quebec Court of Appeal affirmed the trial decision in Dunkin Brands Canada Ltd v. Bertico Inc. establishing a duty on franchisor Dunkin Brands to take reasonable steps to protect and enhance the brand in the face of competition. The effect of the decision will have a lasting and potentially far reaching impact on the duties of parties to franchise agreements.
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Nova Scotia Barristers Society without jurisdiction to refuse Trinity Western University grads
The Nova Scotia Supreme Court ruled late in January that the Nova Scotia Barristers Society ("NSBS") must accredit law degrees granted by Trinity Western University ("TWU") in Langley, British Columbia.
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Chambers Canada Recognizes Lenczner Slaght’s Deep Bench of Expert Litigators
Canada’s leading litigation firm continues to advance their position in the latest edition of the world-renowned directory.
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Lenczner Slaght Litigators Recognized as the Best Lawyers in Canada
In the 2025 edition of Best Lawyers in Canada, Lenczner Slaght is proud to receive 168 total rankings, with 45 of our expert litigators recognized for their expertise across 25 practice areas.
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The 2024 Lexpert Directory Recognizes Lenczner Slaght’s Litigation Excellence
Lenczner Slaght’s litigators continue to be recognized by their peers as the foremost practitioners in their fields.
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Lexpert Recognizes Lenczner Slaght’s Litigation Strength
An increasing number of our expert litigators continue to be recognized as the foremost lawyers in their fields by peers and senior members of the legal profession.
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Chambers Canada Recognizes Lenczner Slaght as a Top-Tier Litigation Firm
Canada’s leading litigation firm and its expert litigators continue to be recognized by world-renowned directory, Chambers & Partners.
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Lenczner Slaght Litigators Recognized as Best Lawyers in Canada
In the latest edition of Best Lawyers in Canada, 41 of our expert litigators are recognized for their expertise across 24 practice areas. The following lawyers have also been recognized as “Lawyer of the Year” for receiving the highest overall peer-feedback in their practice areas in Toronto.
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Lenczner Slaght’s Litigation Excellence Recognized in 2023 Lexpert Directory
Following comprehensive peer review surveys and interviews with senior members in the legal profession, the 2023 Canadian Legal Lexpert Directory has recognized 31 of the firm’s expert litigators for their experience, knowledge, and precision, with 108 rankings spanning 17 practice areas.
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Lenczner Slaght Recognized Among Canada’s Leading Litigation Lawyers
Following an in-depth peer review process, the 2022 Lexpert Special Edition: Canada's Leading Litigation Lawyers guide recognizes 15 Lenczner Slaght lawyers for their extensive courtroom experience and subject-matter expertise. We know courts, and courts know and trust us. That is why clients turn to us to solve their most complex legal problems.
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Lenczner Slaght Ranked Band 1 in Chambers Canada for 5th Consecutive Year
Canada’s leading litigation firm and its expert litigators continue to be recognized in the latest edition of world-renowned directory, Chambers & Partners.
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Lenczner Slaght Litigators Recognized Among the Best Lawyers in Canada
In the latest edition of Best Lawyers in Canada, 39 of our expert litigators are recognized by their peers for their expertise across 24 practice areas.
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Prosecuting and Defending Professional Discipline Cases 2023
Jaan Lilles and Colin Johnston will be sharing their expertise at OsgoodePD's annual program on professional discipline hearings. Jaan will discuss Assessing Duties and Powers while Colin presents on Examinations, Interviews, Inquiries.
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Prosecuting and Defending Professional Discipline Cases 2022
Jaan Lilles and Dena N. Varah were invited to share their expertise at OsgoodePD's annual program on professional discipline hearings. Jaan presented on Assessing Duties and Powers, while Dena presented on Examinations, Interviews, Inquries.
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Prosecuting and Defending Professional Discipline Cases 2020
Jaan Lilles shared his expertise at OsgoodePD's webcast program Prosecuting and Defending Professional Discipline Cases 2020. He presented on the panel Assessing Duties and Powers.
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Prosecuting and Defending Professional Discipline Cases
Jaan Lilles presented at OsgoodePD's Prosecuting and Defending Professional Discipline Cases program. He shared his expertise on the panel discussion Assessing Duties and Powers.
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Transparency and Disclosure Before Administrative Tribunals
Jaan Lilles presented at The Advocates' Society's program titled “Transparency and Disclosure Before Administrative Tribunals”. The program provides an update on the obligations, opportunities, and trends in this area.
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38th Annual Intensive Trial Advocacy Workshop
Monique Jilesen, Risa Kirshblum, Jaan Lilles, and Dena Varah taught at Osgoode Professional Development's 38th Annual Intensive Trial Advocacy Workshop on July 9-15, 2017.
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The Osgoode Certificate in Health Law
Jaan Lilles joined a faculty for the Medical Malpractice: Theory and Practice module for The Osgoode Certificate in Health Law program on April 4, 2017... -
12th Annual Update: Personal Injury Law & Practice
Jaan Lilles joined an expert faculty at Osgoode Professional Development's 12th Annual Update: Personal Injury Law & Practice on September 23... -
The tricky timing of post-judgment mitigation
Jaan Lilles article appeared in the July 10, 2015 issue of the Lawyers Weekly. This article touches on post-judgment trust over employment income earned during the notice period in the event of a wrongful dismissal.
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36th Annual Intensive Trial Advocacy Workshop
Lawrence Thacker, Risa Kirshblum, Monique Jilesen, Eli Lederman, Matthew Sammon, Rebecca Jones, Jaan Lilles and Dena Varah were among the distinguished...
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Benchmark Canada (2018-2024)
Litigation Star – Class Action, Commercial, Professional Liability
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Best Lawyers in Canada (2014-2025)
Administrative and Public Law, Corporate & Commercial Litigation, Health Care Law, Medical Negligence
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Best Lawyers in Canada (2019)
Toronto "Lawyer of the Year" in Health Care Law
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Canadian Legal Lexpert® Directory (2017-2024)
Litigation - Corporate Commercial, Medical Negligence, Professional Liability, Litigation - Regulatory & Public Law (2023)
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Chambers Canada (2023-2025)
Healthcare: Contentious (Nationwide – Canada)
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Lexpert Special Edition: Canada's Leading Health Sciences Lawyers (2021)
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Lexpert Special Edition: Canada's Leading Litigation Lawyers (2022-2023)