Expertise
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Practice Areas:
- Bar Admissions:
- Education:
- Osgoode Hall Law School (2023) OsgoodePD Certificate in Construction Law
- Schulich School of Law, Dalhousie University (2016) JD
- Parsons The New School for Design (2010) AAS (Fashion Design)
- University of Victoria (2008) BFA (Theatre)
Details
- Bio
- Cases
- Associations
- Blog Posts
- News & Media
- Recognition
Kate Costin (she/her)
is an associate at Lenczner Slaght.
Kate’s practice encompasses complex commercial litigation, employment disputes, construction and infrastructure matters, and regulatory proceedings, acting for both prosecution and defence.
Kate has appeared before all levels of court in Ontario, the Alberta Court of King’s Bench, the Saskatchewan Court of King’s Bench, the Saskatchewan Court of Appeal and various administrative tribunals including the Consent and Capacity Board and Human Rights Tribunal.
Prior to attending law school Kate worked on and off Broadway in costume and prop design, and in the costume department for NBC, HBO and F/X Network television and film productions.
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Lithium Royalty Corporation v Orion Resource Partners et al
Counsel to Lithium Royalty Corporation in a successful trial to enforce a binding contract for the purchase of an 85% interest in a Nevada lithium royalty for US$18.7 million total consideration.
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Liam Marshall v College of Psychologists
Counsel to the successful respondent, the College of Psychologists of Ontario, in an appeal to Divisional Court from a decision of the Health Professions Appeal and Review Board confirming the College’s decision not to register the appellant as a psychologist
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Tiger Calcium Services Inc v Clark Sazwan
Counsel to the Plaintiff, Parallel49 in an Alberta action relating to alleged misrepresentations during the purchase and sale of a calcium chloride plant.
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Aecon Mining Construction Services v K+S Potash Canada GP
Counsel to Aecon in complex litigation involving multiple parties and claims, in respect of the Legacy potash mine and production facility in Saskatchewan.
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GolfNorth v Rebel Land Holdings
Counsel to a limited partnership and its general partner in various proceedings contesting the sale of partnership units after the exercise of a right of first refusal.
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TSCC 2282 v Bay-Yorkville Developments
Counsel to the defendant developer in proceedings alleging construction deficiencies in the construction of the Four Seasons Residences in Toronto.
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Ontario Bar Association
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Representative Counsel Not Needed for The Body Shop Employees
In March 2024, The Body Shop Canada (“TBS Canada”) filed a Notice of Intention to make a Proposal under the Bankruptcy and Insolvency Act after its UK parent company completed a cash sweep of TBS Canada. The cash sweep instantly eliminated TBS Canada’s liquidity, forcing it to suspend online orders and close 33 retail stores.
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What’s Control Got to Do With It: Construction Owners are Employers Under the OHSA
On November 10, 2023, when the Supreme Court of Canada (“SCC”) released their decision in R v Greater Sudbury (City), the internet responded with widespread panic because, for the first time, the Court has confirmed that a project owner is an employer under Ontario’s Occupational Health and Safety Act (“OHSA” or the “Act”).
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When intention matters: assessing the enforceability of termination clauses
An invalid termination clause is a former employee’s golden ticket for employment litigation, increasing a notice period from the statutory minimum to what is reasonable at common law. The monetary difference can be substantial. Given the financial implications, there is a large and growing body of case law on when a termination clause will be deemed unenforceable.
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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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Ruling Reinforces Contract Formation Principles During COVID-19 Pandemic
Canadian Lawyer Magazine interviewed Brendan F. Morrison and Kate Costin on their recent trial success, which involved one of the world’s largest lithium mining projects and has reinforced the principles of contract formation in the modern world.
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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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Ontario Court Enforces US$18.7 Million Contract to Purchase Royalty Interest in Mine
Interviewed by Law360 Canada, Brendan F. Morrison and Kate Costin comment on their trial success for Lithium Royalty Corporation, which has significant commercial implications for securities markets and the growing North American lithium industry.
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Lenczner Slaght’s Trial Lawyers Successful in Enforcing Significant Lithium Contract
In a significant trial decision released yesterday in Lithium Royalty Corporation v Orion Resource Partners, our expert litigators were successful in... -
Lenczner Slaght Welcomes Back Chloe, Kate, and Nilou
Lenczner Slaght adds to its collective experience and vast knowledge with the addition of three new associates, bringing Canada’s leading litigation firm to a total of 54 expert litigators.
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Best Lawyers in Canada (2024-2025)
Ones to Watch – Corporate & Commercial Litigation, Labour & Employment Law