Joseph Daniel Duffey (July 1, 1932 – February 25, 2021) was an American academic, educator, anti-war activist and political appointee. He was the Democratic Party's candidate in the 1970 U.S. Senate election in Connecticut, losing to Republican Lowell Weicker. He later served as the Assistant Secretary of State for Educational and Cultural Affairs; the chairman of the National Endowment for the Humanities; the director of the U.S. Information Agency; and the president or chancellor of the University of Massachusetts Amherst, the University of Massachusetts system and American University.