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Heather Treacy

Heather L. Treacy K.C. ICD.D.


Co-chair, Canadian Litigation Group

Very responsive and a subject matter expert on indigenous matters.
Client survey - Thompson Reuters

Heather L. Treacy, K.C. is a highly sought after and nationally recognized counsel whose practice is ‎focused on civil litigation and dispute resolution.‎

Heather is the former Managing Partner of the Calgary office of DLA Piper (2013-2019) and a former ‎‎elected member of DLA Piper’s Executive Committee. She has over 30 years of experience in acting as ‎‎counsel to clients in complex multi-party litigation and disputes, and has extensive experience with ‎negotiations and ‎mediation on matters related to tort law, class actions, energy and resources law, ‎indigenous and constitutional law, general ‎commercial disputes, transportation, aviation, products liability, ‎human rights, employment law, health law and ‎intellectual property law. She frequently appears before both ‎the Trial and Appellate Courts in the Province ‎of Alberta, the Federal Court of Canada, the Federal Court of ‎Appeal and various tribunals, including the ‎Canadian Human Rights Tribunal, energy related tribunals and ‎the Canadian Transportation Agency.‎ In addition to the above, Heather provides legal and governance ‎advice to both public and private sector boards. Heather also chairs the pro bono committee of DLA ‎Piper. ‎‎

Heather also has specific expertise in indigenous law and provides ‎advice on a significant number of issues involving treaty, indigenous rights and indigenous title issues and ‎has been involved in several precedent setting cases, including those in the energy sector.‎

Heather has been recognized for her expertise in the area of dispute resolution by leading lawyer ‎ranking guides Benchmark Canada (Litigation Star), Acritas (Star ‎Lawyer), Chambers Canada, ‎Legal 500 ‎Canada and Euromoney. In the area of indigenous law, she has been recognized by ‎The Canadian Legal Lexpert Directory, Best Lawyers in Canada, Chambers Global and ‎Chambers Canada. In 2014, Heather was named one of WXN’s Top 100, Canada’s Most ‎Powerful Women, in 2016, she was a Women in Law Leadership (WILL) Award winner in the ‎‎“Leadership in the Profession in Private Practice” ‎‎category‎, and in 2017 she was named a ‎winner of the Lexpert Zenith ‎Awards: Celebrating Women in Law. Most recently, Heather was an ‎Excellence Award Recipient in the Woman of the Year category for the 2020 Canadian Law ‎Awards.‎

Heather is active in the community and has a passion for the arts. She is the former Chair of the Board of ‎‎Directors of the Calgary Philharmonic Orchestra. She is a former member of the Board of Directors of the ‎‎University of Calgary Alumni Association. She a former member of the Board of Directors of the Calgary ‎International Language Foundation and currently a member of the Board of Directors of the Calgary French ‎and International School Society.‎

Bar admissionsAlberta, 1990


  • Acting as counsel for a financial institution in relation to claims advanced by 135 Plaintiffs related to ‎‎their RRSP, TFSA and RRIF investments (Andersen v CWT et al).‎
  • Defending a pharmaceutical company in a class action lawsuit involving the sale and marketing of ‎opioids.‎
  • Defended an educational institution in a class action involving allegations of sexual assault.‎
  • Acting as counsel for an energy company on claims related to its patents and royalties. ‎
  • Acting as counsel on various employment related disputes involving allegations of harassment and ‎‎discriminating conduct. ‎
  • Acting as counsel for energy companies on claims involving royalty calculation issues (Stoney Tribal ‎‎‎Council v Petro-Canada Ltd. et al).‎
  • Acted as counsel for a public school board in relation to a judicial review application associated with a ‎‎student lottery admission process (Meyer v CBE). ‎
  • Acting as counsel for a manufacturer in relation to a products liability claim involving agricultural feed ‎‎‎products.‎
  • Acted as counsel for an international air carrier in proceedings advanced by multiple passengers before ‎the Canadian Transportation ‎‎Agency and the Federal Court of Appeal (Swiss International Air Lines Ltd. ‎v CTA et al). ‎
  • Acted as counsel to a manufacturing company involving the protection of its trademark and intellectual ‎‎property.‎
  • Acted as counsel in successfully compelling that an election be held when cancelled by a First Nations ‎‎government (Shotclose et al v Stoney First Nation et al).‎
  • Acted as Chief Federal Negotiator for the Government of Canada in a treaty on Vancouver Island ‎‎involving the B.C. treaty process for First Nations.‎
  • Co-Counsel for Imperial Oil in its application for the Kearl Oil Sands Project before a Joint Review ‎Panel ‎established by the Alberta Energy and Utilities Board and Canadian Environmental Assessment ‎Agency.‎
  • Acted on trespass and royalty claims arising out of the production of oil and gas on reserve lands ‎‎‎(Samson Indian Band et al v Imperial Oil et al).‎
  • Acted as counsel for a financial institution involving an action to trace and recover funds based on ‎‎allegations of bribery (Alberta Treasury Branches v Leahy et al).‎
  • Acted as counsel defending a manufacturer of helicopter parts in relation to a products liability claim.‎
  • Acted as counsel in Federal Court to constitutional challenges to customary aboriginal laws (Letendre v ‎‎Appeal Board of the Horse Lake First Nations; Ashley Paige Horseman v Horse Lake First Nation).‎
  • Acted on injunctive relief and membership issues associated with a First Nation Community (Horseman ‎v ‎Horse Lake First Nation).‎
  • Acted as counsel on a matter as to whether an immigrant who was “overqualified” for a position of ‎‎employment was discriminated on the basis of national or ethnic origin (Sangha v McKenzie Valley ‎Land ‎and Water Board).‎
  • Acted as counsel for an international air carrier in obtaining Anton Piller relief.‎
  • Acted on issues associated with the specific land claim agreement of a First Nation Community ‎‎‎(McAllister v Horse Lake First Nation).‎
  • Acted on determination of reserve interests under Indian Act (Stoney Band v Poucette).‎  ‎
  • English
  • Institute of Corporate Directors, ‎University of Toronto Rotnam ‎School of Management and ‎Haskayne School of Business, ‎ICD.D. (May 2018)‎
  • LL.B., University of Alberta, 1989
  • B.Comm, B. PE University of ‎Calgary, 1984‎


    Music Degrees, Royal Conservatory of Toronto and Mount Royal University, 1984‎


  • Thomson Reuters’ Stand-out Lawyer, 2022
  • Best Lawyers in Canada (Aboriginal/Indigenous Law), 2012-2024; (Energy Law), 2023-2024; (Natural Resources Law), 2024
  • Excellence Award Recipient, The Gowling WLG Award for Woman of the Year,Canadian Law Awards, 2020
  • Winner of the Lexpert Zenith Awards: Celebrating Women in Law, 2017
  • Winner of the Women in Law Leadership (WILL) Awards in the "Leadership in the Profession in Private Practice” category, 2016
  • Recognized as one of Canada's Most Powerful Women: Top 100 WXN, 2014
  • Litigation Star, Benchmark Canada 2014-2024
  • Listed as Acritas Star™ Lawyer 2019-2020
  • Canadian Legal Lexpert® Directory (Aboriginal Law), 2010-2018, 2020-2024
  • Euromoney’s Expert Guides (Litigation and Product Liability) 2016
  • Chambers Canada (Aboriginal Law), 2016-2024; (Litigation: General Commercial - Alberta), 2018-2024
  • Chambers Global (Aboriginal Law), 2015, 2022, 2024
  • Legal 500 Canada (Dispute Resolution), 2016-2024; (Indigenous Law), 2018-2024
  • Martindale-Hubbell, Distinguished® Peer Review Rated
  • Received the distinction and recognition as Queen's Counsel in 2012
  • Recipient of the 1996 Canadian Bar Association Young Lawyers Pro Bono Service Award


  • Panelist, "How Today’s Leaders are Redefining Success and Breaking New Boundaries," The Canadian Law Awards, October 6, 2020
  • Speaker, "First Nations Law: Update on Recent Developments", Calgary Energy Sector Speaker Series, Oct 15, 2015

Media Mentions

Quoted, "A Winding Path for Pipelines", Lexpert Special Edition - Energy, October 2017

Quoted, "Reconciliation Time", Lexpert, June 2016

Community Involvement

  • Member of the Board of Directors and co-Chair of the Governance Committee of the Calgary French ‎and International School Society
  • Past Member of the Board of Directors of the Calgary International Language Foundation
  • Past Member of the Board of Directors and Governance and Nominating Committee of the University of Calgary Alumni Association
  • Past Chair, Vice-Chair of the Board, and Past Chair, Governance Committee and member of the Board of Directors of the Calgary Philharmonic Orchestra
  • Alumni Representative, The University of Calgary Energizing Eyes High Strategic Planning Committee (2016 to 2017)
  • Past member, Board of Directors and Corporate Secretary of the Alberta Ballet Company
  • Past member, Board of Directors of Theatre Junction
  • Past member, Calgary Region Arts Foundation

Memberships And Affiliations

  • Law Society of Alberta
  • Calgary Bar Association
  • Canadian Bar Association
  • International Bar Association
  • Association of International Petroleum Negotiators
  • Institute of Corporate Directors
  • Former Member of the Professional Responsibility Committee of the Law Society of Alberta, 2008 to 2014
  • Former Member of the Law Society of Alberta Pro Bono Committee, 2007-2008
  • Former Member of the Law Society of Alberta Civil Practice Advisory Committee, 2004-2007
  • Executive Member of the National Aboriginal Law Section of the Canadian Bar Association
  • Past Chair, Vice-Chair and Secretary-Treasurer of the Aboriginal Law Section (Southern Alberta) of the Canadian Bar Association
  • Past Chair of the Constitutional Law Section (Southern Alberta) of the Canadian Bar Association