Mary  Paterson

Mary Paterson, Partner, Litigation

Contact Information

  • tel: 416.862.4924
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Bar Admission

Ontario, 2005


  • Osgoode Hall Law School, LL.B.
  • Osgoode Hall Trial Advocacy Course
  • University of Calgary, B.Comm.
  • University of Calgary, B.A. (English)






Mary’s commercial litigation practice focuses on class actions, contract disputes in court or in arbitrations, franchise disputes (including injunctions), assisting financial institutions resolve disputes, and assisting stakeholders in receiverships, bankruptcies and proceedings pursuant to the Companies’ Creditors Arrangement Act. Before joining Osler, Mary clerked at the Court of Appeal for Ontario.

Mary worked to establish several pro bono programs within the firm and has appeared in the Court of Appeal on a pro bono basis numerous times. She won a 2011 Lexpert Zenith Award for her work assisting a UN employee obtain a widower’s benefit after his same-sex partner died while working for the UN.

Notable Matters

  • Several Canadian and global companies in litigation related to alleged breaches of contract.
  • An accounting firm in an alleged wrongful dismissal case.
  • The Greater Toronto Airports Authority in action related to the termination of a contract and taxes.
  • A Canadian bank in a shareholder dispute.
  • An individual in a shareholder dispute.
  • Several Canadian franchisors in franchise disputes.
  • An international company in a patent damages reference (Federal Court).
  • A Canadian company seeking payment from its insurer (Federal Court).
  • A Canadian company successfully resisting an application for leave to bring a derivative action and related oppression actions.
  • A number of Ontario hospitals in disputes with doctors about their privileges and particularly responding to injunctions.
  • Several Canadian Trustees in bankruptcy.
  • Several Canadian court-appointed receivers.
  • An international corporation preparing for proceedings in the United States as well as in Canada under the Companies’ Creditors Arrangement Act.
  • A Canadian secured creditor seeking to appoint a receiver.


  • Law Society of Upper Canada
  • The Advocates’ Society (member of Young Advocates’ Standing Committee, 2007-2010)
  • Young Canadian Arbitration Practitioners, Secretary
  • The Osgoode Society


Pro Bono/Community Work

  • Winner of the 2011 Lexpert Zenith Award for Pro Bono by Associates.
  • Project Work, Board Member
  • Pro Bono Law Ontario, Court of Appeal Amicus Program
  • Pro Bono Law Ontario, Law Help Centre
  • Outside counsel assisting the United Nations Office of Staff Legal Assistance and representing UN employees directly