William Conrad, nascut John William Cann Jr. (Louisville, Kentucky, 27 de setembre de 1920 - Los Angeles, Califòrnia, 11 de febrer de 1994), va ser un actor estatunidenc. Probablement el seu personatge més popular va ser el de l'obès detectiu que donava títol a la sèrie "Cannon", emesa per la cadena CBS entre 1971 i 1976. Posteriorment va protagonitzar també les sèries "Nero Wolfe" (1981) i "Jake and the Fatman" (1987–1992)

William Conrad (September 27, 1920 - February 11, 1994) was an American actor, producer, and director. He was born William Cann in Louisville, Kentucky, the son of a theatre-owner who moved to southern California, where he excelled at drama and literature while at school. Starting work in radio in the late 1930s in California, Conrad went on to serve as a fighter pilot in World War II. He entered the army in 1942, and was commissioned at Luke Field, Arizona in 1943 (now Luke Air Force Base). On the day of his commission he married June Nelson. He returned to the airwaves after the war, going on to accumulate over 7,000 roles in radio by his own estimate.

Among Conrad's various film roles, where he was usually cast as threatening figures, perhaps his most notable role was his first credited one, as one of the gunmen sent to eliminate Burt Lancaster in the 1946 film The Killers. He also appeared in Body and Soul (1947), Sorry, Wrong Number, Joan of Arc (both 1948), and The Naked Jungle (1954).

As a producer for Warner Brothers, he made a string of feature films, including An American Dream (1966, retitled See You in Hell, Darling for British release), A Covenant With Death (1966), First to Fight (1967) and The Cool Ones (1967), and also directed My Blood Runs Cold, Brainstorm and Two on a Guillotine (all 1965).