Caliber 9 (Italian: Milano calibro 9, lit. 'Milan caliber 9'; also released as The Contract) is a 1972 Italian poliziottesco film written and directed by Fernando Di Leo and starring Gastone Moschin, Mario Adorf, Barbara Bouchet, Philippe Leroy, Frank Wolff, Luigi Pistilli, and Lionel Stander.

The film takes its title from the short story collection of the same name by Giorgio Scerbanenco, and is partially based on three of its stories. The musical score was composed by Luis Enriquez Bacalov and performed by the progressive rock band Osanna.

Caliber 9 is the first part in Di Leo's Milieu Trilogy of poliziotteschi films. It was followed by La mala ordina (The Italian Connection) in 1972 and Il Boss (The Boss) in 1973. In 2020, a direct sequel called Calibro 9, was released.