Thomas G. Weiss (born 1946) is a distinguished scholar of international relations and global governance with special expertise in the politics of the United Nations. Since 1998 he has been Presidential Professor at The Graduate Center, CUNY (The City University of New York), and is Director Emeritus of the Ralph Bunche Institute for International Studies.
He is "one of the leading experts on the theory and practice of humanitarian intervention," and is recognized as an authority on international organizations and the United Nations system. Weiss adheres to the constructivist school, and advocates a position for intergovernmental organizations that goes beyond the anarchy of inter-state relations. He initiated the UN Intellectual History Project in 1999 to trace the origins and the evolution of key ideas about international economic and social development nurtured under UN auspices. As a norm entrepreneur, Weiss introduced the idea of the "Third United Nations,” and directed the research team that popularized the concept of Responsibility to Protect. A firm believer in R2P, Weiss has shown in numerous works that a well-grounded interpretation of sovereignty does not preclude intervention in the face of mass atrocities. His oral history transcript is available on the UN Intellectual History Project website.