The term B-movie originally referred to a film designed to be distributed as the "lower half" of a double feature, often a genre film featuring cowboys or gangsters.

The term now generally refers to a low-budget movie with lesser-known (and generally considered lesser-talented) actors. Usually the films are very campy, with cheesy special effects and gratuitous nudity, sexuality and/or violence. The horror movie genre is especially popular. Often B-movies are not even released in theaters, instead going direct-to-video. They spawned a type of late night television show commonly called "Midnight Madness," where they are often shown back-to-back until the early hours of the morning.

Currently, certain production companies such as Troma specialise in producing large quantities of low quality B movies. One of the classic producers of these films was the US company American International Pictures (AIP), founded in 1954 by James H. Nicholson and Samuel Z. Arkoff. Its films include works by Roger Corman, Vincent Price and the early efforts of lesser figures such as Francis Ford Coppola, Robert De Niro and Jack Nicholson.

See also: cult film, Hammer horror, Mystery Science Theater 3000