Sisters (released as Blood Sisters in the United Kingdom) is a 1972 American psychological horror film directed by Brian De Palma and starring Margot Kidder, Jennifer Salt, and Charles Durning. It follows a French Canadian model's separated conjoined twin who is suspected of having committed a brutal murder witnessed by a newspaper reporter in Staten Island, New York City.

Co-written by De Palma and Louisa Rose, the screenplay for the film was inspired by the Soviet conjoined twins Masha and Dasha Krivoshlyapova and features narrative and visual references to several films by Alfred Hitchcock. Filmed on location in Staten Island, the film prominently features split-screen compositions (also present in subsequent De Palma films such as Carrie), and was scored by frequent Hitchcock collaborator Bernard Herrmann.

Released in the spring of 1973, Sisters received praise from critics who noted its adept performances and use of homage. It marked the first thriller for De Palma, who followed it with other shocking thrillers, and went on to become a cult film in the years after its release.