Joan Harrison (26 June 1907 - 14 August 1994) was an English film producer and screenwriter. Born in Guildford, Surrey, Harrison studied at St Hugh's College, Oxford and reviewed films for the student newspaper. She also studied at the Sorbonne. In 1933 Harrison became the secretary of Alfred Hitchcock. Eventually she began reading books and scripts for him and became one of Hitchcock's most trusted associates. When Hitchcock moved to Hollywood in March 1939 to begin his contract with David O. Selznick to direct films, Harrison went with him as an assistant and writer. She gained the title of screenwriter when she wrote the film Jamaica Inn (1939) based on the novel by Daphne du Maurier. Harrison continued writing screenplays for films Rebecca (1940), also adapted from a du Maurier novel, Foreign Correspondent (1940), Suspicion (1941), Saboteur (1942), Dark Waters (1944), and Nocturne (1946). Harrison was an uncredited screenwriter for Ride the Pink Horse (1947) and Your Witness (1950).