Cathy Guirguis


(416) 981-9347
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Cathy is a partner at OKT LLP. Her practice is focussed on advancing Aboriginal and treaty rights through litigation and negotiation. Cathy has represented clients in applications and actions in Ontario and Manitoba, as well as in federal court and at the Supreme Court of Canada. She has also represented Indigenous clients in proceedings and tribunals regarding election processes, labour and employment, and environmental assessment. Cathy provides negotiation advice regarding Aboriginal and treaty rights, land claims, and consultation, and she also advises clients on day-to-day employment matters and governance administration. She received her LL.B. from Osgoode Hall Law School, and she also has a Masters of Environmental Studies.

While at law school, Cathy was a senior editor of the Osgoode Hall Law Journal and she volunteered at Osgoode’s Community Legal Aid Services Program, and Downsview Legal Aid Clinic. She has also worked with the Centre for Indigenous Environmental Resources (CIER), working on projects dealing with the duty to consult and accommodate, and indigenous environmental laws. Prior to law, Cathy worked in international development and she has a background in journalism.

Cathy is a member of the Ontario bar. Cathy is listed as a "consistently recommended" lawyer in the Lexpert Directory.

The Services of Cathy Guirguis are provided through a Professional Corporation.


Representative Work

  • One of the lead counsel representing the Saugeen Ojibway Nation in its Aboriginal title claim to water and claim about the Crown’s fiduciary breach and failure to protect their land, currently before the Ontario Superior Court
  • Lead counsel in a successful judicial review about Ontario’s failure to adequately consult and accommodate the Saugeen Ojibway in respect of aggregate mining in their traditional territory, including the failure to pay reasonable costs of the First Nations’ participation (Saugeen First Nation v. Ontario (MNRF), 2017 ONSC 3456 (CanLII))
  • Represented the Assembly of Manitoba Chiefs in its intervention at the Supreme Court of Canada regarding the Crown’s fiduciary duty to protect Indigenous lands in Williams Lake Indian Band v. Canada [2018] 1SCR 83
  • Represented Athabascan Chipewyan First Nation in responding to Canada’s application to enforce compliance with the First Nations Financial Transparency Act
  • Counsel for Pimicikamak in the Manitoba Court of Queen’s Bench and Manitoba’s Court of Appeal in defence of their rights to be consulted and accommodated about conveyance of culturally significant lands and sites
  • Represented Peguis First Nation in its participation at the Manitoba Clean Environment Commission hearings regarding the Keeyask Generation Project
  • Counsel for First Nations in election disputes about custom election codes in federal court
  • Represented the family in an inquest about an in-custody death of an Indigenous member of Pimicikamak in Thompson, Manitoba

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