Sir Alfred Joseph Hitchcock (13 August 1899 – 29 April 1980) was an English filmmaker. He is widely regarded as one of the most influential figures in the history of cinema. In a career spanning six decades, he directed over 50 feature films, many of which are still widely watched and studied today. Known as the "Master of Suspense", he became as well known as any of his actors thanks to his many interviews, his cameo roles in most of his films, and his hosting and producing the television anthology Alfred Hitchcock Presents (1955–65). His films garnered 46 Academy Award nominations, including six wins, although he never won the award for Best Director despite five nominations.

Hitchcock initially trained as a technical clerk and copywriter before entering the film industry in 1919 as a title card designer. His directorial debut was the British-German silent film The Pleasure Garden (1925). His first successful film, The Lodger: A Story of the London Fog (1927), helped to shape the thriller genre, and Blackmail (1929) was the first British "talkie". His thrillers The 39 Steps (1935) and The Lady Vanishes (1938) are ranked among the greatest British films of the 20th century. By 1939, he had international recognition and producer David O. Selznick persuaded him to move to Hollywood. A string of successful films followed, including Rebecca (1940), Foreign Correspondent (1940), Suspicion (1941), Shadow of a Doubt (1943), and Notorious (1946). Rebecca won the Academy Award for Best Picture, with Hitchcock nominated as Best Director; he was also nominated for Lifeboat (1944) and Spellbound (1945). After a brief commercial lull, he returned to form with Strangers on a Train (1951) and Dial M for Murder (1954); he then went on to direct four films often ranked among the greatest of all time: Rear Window (1954), Vertigo (1958), North by Northwest (1959) and Psycho (1960), the first and last of these garnering him Best Director nominations. The Birds (1963) and Marnie (1964) were also financially successful and are highly regarded by film historians.

The "Hitchcockian" style includes the use of editing and camera movement to mimic a person's gaze, thereby turning viewers into voyeurs, and framing shots to maximise anxiety and fear. The film critic Robin Wood wrote that the meaning of a Hitchcock film "is there in the method, in the progression from shot to shot. A Hitchcock film is an organism, with the whole implied in every detail and every detail related to the whole." Hitchcock made multiple films with some of the biggest stars in Hollywood, including four with Cary Grant in the 1940s and 1950s, three with Ingrid Bergman in the second half of the 1940s, four with James Stewart over a decade commencing in 1948, and three consecutive with Grace Kelly in the mid-1950s. Hitchcock became an American citizen in 1955.

In 2012, Hitchcock's psychological thriller Vertigo, starring Stewart, displaced Orson Welles' Citizen Kane (1941) as the British Film Institute's greatest film ever made based on its world-wide poll of hundreds of film critics. As of 2021, nine of his films had been selected for preservation in the United States National Film Registry, including his personal favourite, Shadow of a Doubt (1943). He received the BAFTA Fellowship in 1971, the AFI Life Achievement Award in 1979, and was knighted in December of that year, four months before his death on 29 April 1980.