Cecil Blount DeMille (; August 12, 1881 – January 21, 1959) was an American film director, producer and actor. Between 1914 and 1958, he made 70 features, both silent and sound films. He is acknowledged as a founding father of the American cinema and the most commercially successful producer-director in film history. His films were distinguished by their epic scale and by his cinematic showmanship. His silent films included social dramas, comedies, Westerns, farces, morality plays, and historical pageants. He was an active Freemason and member of Prince of Orange Lodge #16 in New York City.

DeMille was born in Ashfield, Massachusetts, and grew up in New York City. He began his career as a stage actor in 1900. He later moved to writing and directing stage productions, some with Jesse Lasky, who was then a vaudeville producer. DeMille's first film, The Squaw Man (1914), was also the first full-length feature film shot in Hollywood. Its interracial love story made it commercially successful and it first publicized Hollywood as the home of the U.S. film industry. The continued success of his productions led to the founding of Paramount Pictures with Lasky and Adolph Zukor. His first biblical epic, The Ten Commandments (1923), was both a critical and commercial success; it held the Paramount revenue record for twenty-five years.

DeMille directed The King of Kings (1927), a biography of Jesus, which gained approval for its sensitivity and reached more than 800 million viewers. The Sign of the Cross (1932) is said to be the first sound film to integrate all aspects of cinematic technique. Cleopatra (1934) was his first film to be nominated for the Academy Award for Best Picture. After more than thirty years in film production, DeMille reached a pinnacle in his career with Samson and Delilah (1949), a biblical epic which became the highest-grossing film of 1950. Along with biblical and historical narratives, he also directed films oriented toward "neo-naturalism", which tried to portray the laws of man fighting the forces of nature.

He received his first nomination for the Academy Award for Best Director for his circus drama The Greatest Show on Earth (1952), which won both the Academy Award for Best Picture and the Golden Globe Award for Best Motion Picture – Drama. His last and best known film, The Ten Commandments (1956), also a Best Picture Academy Award nominee, is currently the eighth-highest-grossing film of all time, adjusted for inflation. In addition to his Best Picture Awards, he received an Academy Honorary Award for his film contributions, the Palme d'Or (posthumously) for Union Pacific (1939), a DGA Award for Lifetime Achievement, and the Irving G. Thalberg Memorial Award. He was the first recipient of the Golden Globe Cecil B. DeMille Award, which was named in his honor. DeMille's reputation had a renaissance in the 2010s and his work has influenced numerous other films and directors.