People Mentioned
National Co-Chair, Calgary
Osler congratulates Maureen Killoran, KC, our National Co-Chair, on being recognized as one of Canada’s Top 25 Most Influential Lawyers by Canadian Lawyer, in their 2025 survey of readers, peers and editorial board.
Recognized in the Business category for her visionary leadership and exceptional contributions to Canadian industry, business and legal communities, Maureen maintains a full litigation practice while serving as National Co-Chair of Osler. She was the first woman in Alberta to serve as Managing Partner of a national law firm when she was tapped to lead Osler’s Calgary office from 2011 to 2017. Now the National Co-Chair of Osler and one of our most senior leaders responsible for the strategic direction and business of the firm, Maureen accomplishes all of this while maintaining a full and dynamic litigation practice. Under her business leadership, Osler has both strengthened its national presence and deepened its local influence in the Calgary and Vancouver markets.
In her career, Maureen has shaped Canadian jurisprudence through landmark decisions, including through her role as lead litigation counsel on the Trans Mountain Pipeline Extension Project. She successfully defended all regulatory appeals, judicial reviews and challenges to the nation building project. Maureen’s successful advocacy has driven pivotal Canadian business and resource development outcomes including through constitutional reference cases at the Supreme Court of Canada.
A leading litigator, Maureen has had many “firsts”, broken barriers and championed women’s leadership, solidifying her role as a true trailblazer in the Canadian legal community. She has appeared in virtually every province in Canada, the Federal Court, the Federal Court of Appeal and the Supreme Court of Canada. In 2025, she was inducted as a Fellow of the American College of Trial Lawyers and is routinely recognized by trade publications as among the best advocates in Canada. As a trusted legal and business advisor, clients applaud Maureen for her “understanding of the business”, “outstanding judgment, creativity, and thoughtful, practical advice”.
Under Maureen’s visionary leadership, Osler’s Calgary and Vancouver offices have expanded, significantly enhancing the firm’s presence and influence in these critical economic hubs. Her leadership and strategic acumen have been instrumental in shaping the firm’s direction and fostering a culture of excellence.
As part of Canadian Lawyer’s 16th annual survey, Maureen was selected based on her work and broader contributions that influenced the legal system over the last 18 months.
In business, law and community, Maureen leads with purpose and a stated desire to “leave the place — one’s firm, community, city, province and country — better than you found it.” In addition to exercising visionary strategic and business leadership, she mentors future generations, champions women’s leadership, and contributes to a legal profession rooted in excellence, equity and impact. She has played a crucial role in mentoring generations of lawyers — particularly women — by leading with guidance and support. Her goal is to increase the number of women at Osler, within the partnership and across the broader legal and business communities.
Each year Canadian Lawyer’s Top 25 Most Influential Lawyers list recognizes individuals who help shape the law and elevate the strength and quality of legal service in Canada. These lawyers are chosen across five different categories from hundreds of nominees for their impact on nationally significant legal issues.
Read Canadian Lawyer’s announcement about the award.
People Mentioned
National Co-Chair, Calgary
