motion picture calculated to cause intense repugnance, fear, or dread. Horror films may incorporate incidents of physical violence and psychological terror; they may be studies of deformed, disturbed, psychotic, or evil characters; stories of terrifying monsters or malevolent animals; or mystery thrillers that use atmosphere to build suspense. The genre often overlaps science fiction films and film noir.

The great popular success of Dracula (made in the United States in 1931), Frankenstein (1931), and The Mummy (1932) led to a long series of successful horror films including King Kong (1932) and The Black Cat (1934). Among some of the best-known horror classics of this period are The Werewolf of London (1935), The Wolf Man (1941), and Cat People (1942).

The influence of science fiction can be seen in horror films of the 1950s about monsters from other planets (The Thing, 1951) and mutations of ordinary animals (Them!, 1954). Japanese studios released monster films, such as Gojira (1954; Godzilla) and Radon (1956; Rodan), while British companies such as Hammer Studios shifted the emphasis from atmospheric terror to scenes of bloody violence in motion pictures such as The Curse of Frankenstein (1957) and The Horror of Dracula (1958). Sophisticated films of the mystery-thriller type, such as Alfred Hitchcock's (Hitchcock, Sir Alfred) Psycho (1960) and Roman Polanski's (Polanski, Roman) Repulsion (1965), continued to be made. Over time the horror film genre came to be represented by several subgenres, including films about the supernatural, such as The Exorcist (1973) and The Shining (1980); the “psycho-slasher” films, perhaps best represented by John Carpenter's Halloween (1978); and science fiction thrillers, such as Ridley Scott's Alien (1979). The popularity of B-grade, low-budget horror films grew with the introduction in the 1970s of the videocassette and cable television.