Expertise
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Practice Areas:
- Bar Admissions:
- Education:
- University of Toronto (2001) JD (Honours Standing)
- University of Toronto (1998) MA
- Carleton University (1997) BA (Highest Honours)
Details
- Bio
- Cases
- Associations
- Blog Posts
- News & Media
- Publications & Presentations
- Recognition
Matthew Sammon
"Matt Sammon is a warrior of a litigator. He is fearless and takes on strong cases. His skill at cross-examination is unparalleled. He is one of the best in the country." — Chambers Canada
Recognized as a leading and formidable trial counsel, Matthew has extensive litigation experience across a broad range of areas, including complex corporate and commercial litigation, professional liability and medical malpractice, and employment cases.
After 20 years of practice at Lenczner Slaght, Matthew is now one of the most experienced civil trial lawyers of his generation, having conducted trials, applications, and arbitrations in myriad areas, including infrastructure and construction, complex commercial proceedings, insurance, medical litigation, professional liability, and employment disputes.
Matthew's experience as lead counsel for constructors in complex infrastructure and construction disputes in Ontario and other jurisdictions has earned him recognition as one of Canada's leading infrastructure lawyers.
His roster of clients has included large and mid-sized corporations across a wide range of sectors, including construction, financial services, insurance, banking, telecommunications, retail, health care, manufacturing, hospitality, and oil and gas. He also acts regularly for executives and other individuals in civil and regulatory disputes.
Matthew also has deep experience in professional regulation and medical malpractice litigation, appearing regularly as lead counsel in complex medical litigation and regulatory proceedings.
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College of Physicians and Surgeons of Ontario v Luthra
Counsel to the moving-party physician in successfully bringing a motion to obtain third-party records before the Ontario Physicians and Surgeons Discipline Tribunal. The requested records were obtained and produced after being found likely relevant and their production determined to be in the interests of justice.
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Chief Rupert Meneen v Jeffrey RW Rath
Co-counsel (along with OKT LLP) to Chief Rupert Meneen and the Tallcree First Nation in proceedings commenced against the Respondents, Jeffrey Rath and his professional firm, to recover and protect assets of the Tallcree First Nation Trust. In these ongoing proceedings, Chief Meneen has obtained orders replacing Mr. Rath’s professional corporation as trustee of the Trust, granting a Mareva injunction over the assets of the Respondents, and appointing an investigative receiver, among other relief.
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Counsel to a Block Developments Inc. in a successful five-week trial against Brewers Retail Inc. (i.e., The Beer Store). Block Developments Inc. was awarded $15.5 million for breach of contract and misrepresentation in respect of two failed land acquisitions in Toronto. Brewers Retail Inc. commenced an appeal, which we successfully defended. The damages award of $15.5 million was upheld.
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Mosaic Transit Partners General Partnership v Ontario Infrastructure and Lands Corporation
Counsel to Mosaic Transit Partners General Partnership in an application against Infrastructure Ontario and Metrolinx about the Finch West LRT transit project. Mosaic successfully resisted the Respondents’ motion to stay the application in favour of arbitration. Mosaic was also successful in its motion for production of a contested document.
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Counsel to Shopify in defending a wrongful dismissal claim brought by a former employee seeking significant damages, including for restricted share units and stock options.
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Redline Steel LLC v Shopify Inc
Counsel to Shopify, a Canadian multinational e-commerce company, in defending a USD $60 million claim relating to alleged technical issues in various marketing features implemented across Shopify and Meta’s storefronts.
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Abid Chaudry v Bank of Montreal
Counsel to the Bank of Montreal in defending a wrongful dismissal claim brought by a senior managerial employee. Successfully resisted several motions and subsequent appeals brought by the Plaintiff, including a motion to amend the Statement of Claim and a motion to compel answers to refusals.
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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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Mittra v Royal Bank of Canada et al
Counsel to RBC in successfully defending a $10 million wrongful dismissal claim. After a three-week trial, the Court held that RBC had just cause to dismiss the plaintiff without notice.
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Ratz-Cheung v BMO Nesbitt Burns Inc
Counsel to the defendants, Bank of Montreal, in defending an action by a former employee in a matter involving damages for breach of contract and wrongful dismissal.
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The Advocates' Society
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Quorum Club - Advisory Board (2025-present)
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Canadian Bar Association
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Ontario Bar Association
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5-Year Retrospective: Top 10 Noteworthy Cases
Matthew Sammon and Andrew Locatelli's blog, 5-Year Retrospective: Top 10 Noteworthy Cases, was published on commerciallist.com as part of the Commercial List Year in Review: 5-Year Retrospective (2021-2025) guide. In this blog, they examine 10 noteworthy commercial decisions between 2021 and 2025, each offering practical lessons that extend beyond the facts of the individual case. Taken together, these decisions provide a roadmap for litigators, in-house counsel, and business leaders navigating the complexities of modern commercial disputes.
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Canadian Courts May Set Aside Valid Arbitration Agreements to Remedy Oppression
In Tsa Corporation v KPMG LLP, the Supreme Court of the Northwest Territories confirmed that courts may set aside valid arbitration agreements as a just and proper remedy for oppression. The decision underscores that arbitration will not shield parties from court scrutiny when agreements are tainted by oppressive misconduct.
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Court Puts Bankers on Notice: “Exceptional” Integrity and Honesty Required
After a three-week trial, the Ontario Superior Court has held that the Royal Bank of Canada had after-acquired cause to terminate a senior banker, Aidan Mittra, and dismissed Mittra’s $10‑million lawsuit.
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Chambers Canada Highlights Lenczner Slaght as a Litigation Powerhouse
With 28 ranked lawyers and top-tier practice group rankings across 11 areas, Lenczner Slaght’s latest Chambers Canada results continue to reinforce that its reputation as Canada’s leading litigation firm is built on decades of courtroom excellence, national reach, and top-tier client service.
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49 Lenczner Slaght Litigators Named in Best Lawyers in Canada 2027
In the 2027 edition of Best Lawyers in Canada, 49 of our expert litigators earned 172 rankings across 26 practice areas, a testament to the depth and breadth of our advocacy.
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Insolvency Insider Canada featured Matthew Sammon, Jessica Kras, and Natalie Workewych, resharing their blog on the Alberta Court of King's Bench's decision to grant a worldwide Mareva injunction and appoint an investigative receiver. Our expert litigators discuss how the court acted to protect and trace more than $8.5 million removed from the Tallcree First Nation Trust, after finding a real risk that the former trustee could interfere with recovery efforts. The decision also reflects broader concerns over his administration of First Nations trust assets.
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Lenczner Slaght’s Matthew Sammon, Jessica Kras, and Natalie Workewych, acting alongside OKT LLP, have secured significant interim relief for Chief Rupert Meneen and Tallcree First Nation in ongoing litigation to recover and protect assets of the Tallcree First Nation Trust.
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Alberta Judge Extends Order Freezing Separatist Lawyer’s Assets in Legal Dispute With First Nation
In a CBC News article, Matthew Sammon is interviewed following our success in securing an extension of a Mareva injunction freezing assets linked to the Tallcree First Nation Trust’s $57.6-million agricultural benefits settlement.
Lenczner Slaght’s Matthew Sammon, Jessica Kras, and Natalie Workewych represent Chief Rupert Meneen and the Tallcree First Nation in ongoing litigation to recover and protect assets of the Tallcree First Nation Trust.
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Judge Extends Injunction Freezing Millions of Alberta Separatist Leader’s Assets
In a statement to CP24, Matthew Sammon commented on Justice John Gill's decision to extend and expand a Mareva injunction freezing Jeffrey Rath's assets and appoint an investigative receiver to trace funds removed from the Tallcree First Nation trust.
Lenczner Slaght’s Matthew Sammon, Jessica Kras, and Natalie Workewych have secured significant interim relief for Chief Rupert Meneen and the Tallcree First Nation in ongoing litigation to recover and protect assets of the Tallcree First Nation Trust.
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Judge Issues Extended Freezing Order on Alberta Separatist Lawyer's Assets
Matthew Sammon was featured in the Edmonton Journal on Justice John Gill’s decision to grant an indefinite, extended freezing order on $8.5 million in assets belonging to Jeffrey Rath, following Chief Rupert Meneen's application to remove Jeffrey from overseeing the Tallcree First Nation's nearly $15 million in trust funds.
Lenczner Slaght’s Matthew Sammon, Jessica Kras, and Natalie Workewych have secured significant interim relief for Chief Rupert Meneen and the Tallcree First Nation in ongoing litigation to recover and protect assets of the Tallcree First Nation Trust.
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Lawsuit Accuses Winnipeg Woman of Taking $6M From Non-profit to Fund Vacations, Buy Tiktok Coins
Featured in CBC News, Matthew Sammon commented on the National Guardians Network’s efforts to recover millions of dollars in allegedly misappropriated funds and continue supporting Indigenous guardianship programs without interruption. The article examines allegations that the organization’s former financial director diverted over $6 million in federal funding intended for Indigenous conservation initiatives toward personal expenses and unauthorized transactions.
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Lenczner Slaght Celebrates 25 Years on the Lexpert Bull’s-Eye
The 2026 Canadian Legal Lexpert Directory continues to recognize Lenczner Slaght as the #1 firm in Toronto for Litigation and Commercial Litigation.
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NWT First Nation Claim Against KPMG Permitted to Proceed
Featured in The Globe and Mail, Matthew Sammon commented on the Supreme Court of the Northwest Territories' novel approach to the oppression remedy, ensuring our client, the Lutsël K'é Dene First Nation, could be heard in open court and pursue recovery of more than $10 million in alleged fraud.
Lenczner Slaght is proud to have secured an important commercial win for our client, the Łutsël K'é Dene First Nation.
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Matthew Sammon will share his expertise at the Quorum Club on two important topics. He’ll present on the panel AI, Innovation, and the New Strategic Advisor, exploring how legal leaders can build meaningful AI governance without stifling innovation. He will also lead the panel Beyond Law: Expanding Portfolios, examining the general counsel’s expanding mandate and what it takes to manage that growth without losing focus on the core legal role.
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Commercial List Year in Review 5-Year Retrospective (2021-2025)
This guide offers data-driven analysis on all decisions published on CanLII from 2021-2025, an overview of the top 10 noteworthy cases, as well as key developments in insolvency matters, shareholder disputes, injunctions, and securities litigation.
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2025 Snapshot: Through the Lens of Lenczner Slaght
We’ve released our 2025 Snapshot, highlighting the most significant developments, decisions, and trends in litigation from the past year across 21 practice areas. Reflect on 2025 and look ahead to 2026 through the lens of our expert litigators.
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Digital Deception: How Online Marketplaces Fuel Fraud and Organized Crime
Matthew Sammon was invited to share his expertise at the Quorum Club. Matthew presented on the panel titled, Digital Deception: How Online Marketplaces Fuel Fraud and Organized Crime.
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2024 Snapshot: Through the Lens of Lenczner Slaght
Lenczner Slaght launches our 2024 Snapshot, which highlights the most significant developments, decisions, and trends in litigation from the past year across 20 areas of expertise. Reflect on 2024 and look ahead to 2025 through the lens of our expert litigators.
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2023 Snapshot: Through the Lens of Lenczner Slaght
Lenczner Slaght launches our 2023 Snapshot, a look at the most significant developments, decisions, business takeaways, and trends in litigation from the last year, across 15 practice areas. Revisit 2023 and look ahead to 2024 through the lens of our expert litigators.
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Civility in a Post-Pandemic Era
Matthew Sammon presented at The Advocates' Society's program Civility in a Post-Pandemic Era on the panel "Litigator v. The Courtroom: Scenarios for Discussion".
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Matthew Sammon spoke at the OBA's Young Lawyers Division program Your First Civil Trial. He shared his expertise on the panel “Top 10 Trial Mistakes and How to Avoid Them".
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Defamation in the Social Media Sphere
Matthew Sammon spoke at the Ontario Bar Association's program Social Media and Internet Law: Your Comprehensive Guide. He shared his expert insight on the social media landscape and how to keep pace with this evolving area of the law.
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Matthew Sammon and Risa Kirshblum spoke at the 2018 National Conference & World Summit. This panel of employment litigators and experienced in-house counsel shared practical tips on topics including non-competition and non-solicitation provisions, confidentiality obligations, employees duties’ to former employers and steps to respond to and manage improper departures.
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Benchmark Canada (2015-2025)
Litigation Star – Commercial, Professional Liability
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Benchmark Canada (2019)
Labour Employment Attorney of the Year
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Best Lawyers in Canada (2014-2027)
Construction Law, Corporate & Commercial Litigation, Health Care Law, Labour & Employment Law, Medical Negligence
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Best Lawyers in Canada (2022)
Toronto "Lawyer of the Year" in Medical Negligence
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Canadian Legal Lexpert® Directory (2013-2026)
Construction Law, Litigation - Corporate Commercial, Medical Negligence, Professional Liability, Litigation - Defamation & Media, Employment Law (Employer)
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Chambers Canada (2020-2027)
Construction (Nationwide – Canada); Employment & Labour: Non-Unionised Employees; Healthcare: Contentious (Nationwide – Canada); Employment & Labour (Ontario)
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Lexology Index: Commercial Litigation (2018-2019, 2023-2025)
Future Leader
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Lexpert Guide to the Leading US/Canada Cross-border Litigation Lawyers in Canada (2014-2017)
Corporate Commercial Litigation, Litigation Lawyer to Watch (2014)
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Lexpert Rising Stars (2013)
Leading Lawyers Under 40
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Lexpert Special Edition: Canada's Leading Health Sciences Lawyers (2021, 2025-2026)
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