Leon Castellanos-Jankiewicz

León Castellanos-Jankiewicz is Senior Researcher in International Law at the Asser Institute, and supervisor of the International Law Clinic on Access to Justice for Gun Violence at the University of Amsterdam Faculty of Law. His work focuses on the human rights implications of irresponsible arms trade and the history of public and private international law.

Castellanos-Jankiewicz regularly advises governments on arms export policies, and leads the project on 'Enabling Civil Society Efforts to Address the Misuse, Diversion and Abuse of Arms Exports in Latin America' within the Asser Institute, which was awarded a competitive grant by the U.S. State Department (2023-2025).

He has lectured in universities across Europe in English, Spanish and French. Overtime, he has written for print and online publications including El País, NRC and Just Security. He is a listed expert in the Forum on the Arms Trade and sits on the Advisory Committee of Global Action on Gun Violence.

Previously, he was Max Weber Postdoctoral Fellow at the European University Institute and has held visiting positions at the University of Giessen (2023), the University of Cambridge (2017) and Harvard Law School (2015-16). He is the inaugural recipient of the David D. Caron Prize of the American Society of International Law (2019) and holds a PhD in International Law from the Geneva Graduate Institute.