Leonard P. Liggio (July 5, 1933 – October 14, 2014) was a classical liberal author, research professor of law at George Mason University and executive vice president of the Atlas Network in Fairfax, Virginia.
In 1965, Liggio gave lectures with Russell Stetler on "Imperialism and Anti-Imperialism: The Ideological Question in Vietnam" for the newly founded Free University of New York.
He was a distinguished senior scholar with the Institute for Humane Studies, where he served as director of Programs in History and Social Theory from 1974 to 1977, as executive vice-president from 1979 to 1980 and then as president from 1980 to 1989.
In 1958, he attended his first meeting of the Mont Pelerin Society in the United States, held at Princeton University.
In 1965, with Murray Rothbard and George Resch, Liggio created Left and Right: A Journal of Libertarian Thought, a publication which emphasized "common philosophical bonds uniting the anarchism and isolationism of the Old Right, and the instinctive pacifistic anarchism characterizing the New Left in the middle sixties".