Robin Hahnel (March 25, 1946) is an economist and political activist. He politically considers himself a product of the 1960s American New Left movement and a supporter of libertarian socialism. He is a theorist of participatory economics.

He has been active in many social movements and organizations for 40 years, especially active in the student movements opposed to the US invasion of South Vietnam. Most recently he has participated in the United States Green Party. Hahnel's work in economic theory and analysis is influenced by Marx, Keynes, Piero Sraffa, Michał Kalecki, and Joan Robinson. It should be noted that he has worked as a teacher in Cuba, Peru and England.

Hanhel was a student at Harvard when he met Michael Albert, who was studying at MIT. During three decades the duo formed by both produced seven books. Among the early works was "Marxism and Socialist Theory", an evaluation of Marxist and Marxist-Leninist theory that underscored what they believed to be flaws. They subsequently produced "Socialism Today and Tomorrow," which was an analysis of the then reigning socialism in the Soviet Union, China, and Cuba, as well as an outline of an alternative theoretical framework for socialism.