Alfred Unser (May 29, 1939 – December 9, 2021) was an American automobile racing driver, the younger brother of fellow racing drivers Jerry and Bobby Unser, and father of Al Unser Jr. He was the second of four men (A. J. Foyt, himself, Rick Mears and Hélio Castroneves) to have won the Indianapolis 500 four times (1970, 1971, 1978, 1987), the fourth of five to have won the race in consecutive years, and won the National Championship in 1970, 1983, and 1985. The Unser family has won the Indy 500 a record nine times. He was the only person to have both a sibling (Bobby) and child (Al Jr.) as fellow Indy 500 winners. Al's nephews Johnny and Robby Unser have also competed in that race. In 1971, he became the only driver to date to win the race on his birthday (his 32nd).

After his son Al Unser Jr. joined the national championship circuit in 1983, Unser was generally known by the retronyms "Al Unser Sr." or "Big Al."