Osseiran Law

About Osseiran Law

Osseiran Law is a small litigation firm based in Toronto, with a second office in Ottawa. The practice centers on a single principal lawyer, Marwan Osseiran, called to the bar in Ontario in 2008 after a law degree in Beirut, an LL.M. in American law from Boston University, a comparative law masters from McGill focused on competition law, and further graduate study in international criminal law at Leiden University. The firm's caseload covers criminal defence, civil litigation, insurance and banking disputes, regulatory and quasi-criminal proceedings, and federal court matters.

An international human rights practice runs alongside that Canadian caseload. Osseiran was admitted as counsel before the International Criminal Court in 2018, and later took on credentials at the Kosovo Specialist Tribunal and as legal representative for victims before the Special Tribunal for Lebanon. Since 2020, Osseiran has been on the list of counsel appointed by the Office of the Ombudsperson of the UN Security Council's Sanctions Committee, and was called to the Bar of England and Wales through Middle Temple in 2021. It started closer to home: Osseiran began as duty counsel with Legal Aid Ontario at Old City Hall, and from 2015 to 2017 represented refugees and survivors of war crimes in Ontario courts. Osseiran works in English, French, and Arabic.