Margaret O'Sullivan

Managing Partner at O'Sullivan Estate Lawyers

Speaker

Margaret’s practice involves all aspects of trust and estate work for domestic and international private clients, including estate planning; will and trust planning; incapacity planning; estate litigation; advising executors, trustees and beneficiaries and administration of estates and trusts, with a focus on high net worth domestic, cross border and multijurisdictional succession issues.

Margaret is recognized in The Best Lawyers in Canada 2025, Legal Week’s Private Client Global Elite 2026 representing the top 250 private client lawyers worldwide, in the 2025 Edition of The Canadian Legal Lexpert Directory as one of the most frequently recommended estate planning lawyers and as a thought leader, in The Who’s Who Legal: Private Client 2025 and in The Who’s Who Legal: Canada 2025.

She is one of nine top-ranked Band 1 private wealth client lawyers in Canada in Chambers High Net Worth 2025 Guide.

Her firm was selected as one of the “Top 10 Wills, Trusts and Estates Boutiques” by Canadian Lawyer Magazine for 2023-24.

She is the recipient of the 2014 Society of Trust and Estate Practitioners (STEP) Founder’s Award for Outstanding Achievement and the Ontario Bar Association’s 2013 Award of Excellence in Trusts and Estates Law.

Prior to establishing an independent practice, Margaret was a partner in the Toronto office of the national Canadian law firm Stikeman Elliott where she directed the firm’s trusts and estates practice.

She has practiced exclusively in the area of trusts and estates since her call to the bar in 1983.