Rosemary's Baby is a 1968 American psychological horror film written and directed by Roman Polanski, based on Ira Levin's 1967 novel of the same name. The film stars Mia Farrow as a newlywed living in Manhattan who becomes pregnant, but soon begins to suspect that her neighbors are members of a Satanic cult who are grooming her in order to use her baby for their rituals. The film's supporting cast includes John Cassavetes, Ruth Gordon, Sidney Blackmer, Maurice Evans, Ralph Bellamy, Patsy Kelly, Angela Dorian, and Charles Grodin in his feature film debut.

Psychological horror is a subgenre of horror and psychological fiction with a particular focus on mental, emotional, and psychological states to frighten, disturb, or unsettle its audience. The subgenre frequently overlaps with the related subgenre of psychological thriller, and often uses mystery elements and characters with unstable, unreliable, or disturbed psychological states to enhance the suspense, horror, drama, tension, and paranoia of the setting and plot and to provide an overall creepy, unpleasant, unsettling, or distressing atmosphere.