Gad Avigad (Hebrew גד אביגד; born 1930) is an Israeli biochemist.
Avigad was born in 1930 in Jerusalem. At 17, he joined the ranks of the Palmach. He studied at the Hebrew University of Jerusalem, receiving a doctorate in 1958.
Avigad was Associate Professor of Biochemistry at the Hebrew University and, in 1970, moved to the United States and taught at the Robert Wood Johnson Medical School in New Jersey.
In 1957, Avigad was awarded the Israel Prize, in exact sciences, jointly with Shlomo Hestrin and David Sidney Feingold, with whom he studied.