Josiah MacQuarrie

Senior Counsel

4800 – 100 King Street West
Toronto, Ontario, M5X 2A2

Clerk

Bar Admissions

  • Ontario, 2010

Education

  • LL.B., Dalhousie Law School (2009)
  • M.A. (with merit), University of Birmingham (2005)
  • B.A. (Honours), Mount Allison University (2004)

Professional Accreditations and Affiliations

  • Law Society of Ontario
  • The Advocates’ Society
  • Canadian Defence Lawyers
  • Ontario Bar Association

About Lawyer

Josiah joined Aviva Trial Lawyers as Senior Counsel in April 2026.  His practice focuses on the defence of first and third party property claims, construction, and product liability.  He also provides insurance coverage advice on commercial general liability, builder’s risk, wrap-up liability, automobile and homeowner’s policies. He has conducted applications, trials and appeals and has appeared at all levels of court in Ontario.

Prior to joining Aviva Trial Lawyers, Josiah was a Senior Partner at a well-known insurance defence firm.  He also acted as a private mediator.  He has a keen interest in alternative dispute resolution and completed the ADR Workshop with the Stitt Feld Handy Group in 2023.

Notable Cases

  • Lower Williams Properties Ltd. v. Santaguida, 2025 ONSC 1132
  • Forest Hill Fine Homes Inc. v. Heartland Farm Mutual Insurance Co., 2023 ONCA 171 (CanLII)
  • GFL Infrastructure Group Inc. v. Temple Insurance Company, 2022 ONCA 390 (CanLII)
  • Persaud v. Bascom, 2021 ONSC 4398 (CanLII)
  • Aviva Insurance Company of Canada v. Parrsboro Metal Fabricators, 2017 CarswellOnt 17 (Ont. S.C.J.)
  • 111 St. Clair Avenue West Investments v. Ron Boyko Group Inc. 2015 CarswellOnt 10884 (Ont. S.C.J.)
  • Kiden Used Furniture v. Pearson, 2015 CarswellOnt 3322 (Ont. C.A.)

Personal Interests

Josiah is a lifelong skier and an avid record collector.  He enjoys reading, music and travel.