A monster movie, monster film, creature feature or giant monster film is a film that focuses on one or more characters struggling to survive attacks by one or more antagonistic monsters, often abnormally large ones. The film may also fall under the horror, comedy, fantasy, or science fiction genres. Monster movies originated with adaptations of horror folklore and literature.

A monster is a type of fictional creature found in horror, fantasy, science fiction, folklore, mythology and religion. Monsters are very often depicted as dangerous and aggressive, with a strange or grotesque appearance that causes terror and fear, often in humans. Monsters usually resemble bizarre, deformed, otherworldly and/or mutated animals or entirely unique creatures of varying sizes, but may also take a human form, such as mutants, ghosts, spirits, zombies, or cannibals, among other things. They may or may not have supernatural powers, but are usually capable of killing or causing some form of destruction, threatening the social or moral order of the human world in the process.