William Charles Ayers (; born December 26, 1944) is a former leader of the Weather Underground and American elementary education theorist. During the 1960s, Ayers participated in the counterculture movement that opposed US involvement in the Vietnam War. He is known for his 1960s radical activism and his later work in education reform, curriculum and instruction.
In 1969, Ayers co-founded the Weather Underground, a self-described Communist revolutionary group that sought to overthrow imperialism. The Weather Underground conducted a campaign of bombing public buildings (including police stations, the United States Capitol, and the Pentagon) during the 1960s and 1970s in response to U.S. involvement in the Vietnam War.
Ayers is a retired professor in the College of Education at the University of Illinois at Chicago, formerly holding the titles of Distinguished Professor of Education and Senior University Scholar. During the 2008 U.S. presidential campaign, a controversy arose over his contacts with then-candidate Barack Obama. He is married to Bernardine Dohrn, who was also a leader in the Weather Underground.