William Peter Blatty (January 7, 1928 – January 12, 2017) was an American writer, director and producer. He is best known for his 1971 novel The Exorcist and for his screenplay for the 1973 film adaptation.

Blatty won an Academy Award for Best Adapted Screenplay for The Exorcist, and was nominated for Best Picture as its producer. The film also earned Blatty a Golden Globe Award for Best Motion Picture – Drama as producer. Born and raised in New York City, Blatty received his bachelor's degree in English from Georgetown University in 1950, and his master's degree in English literature from the George Washington University.