Caliber 9 is a 1972 Italian noir-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.

Poliziotteschi constitute a subgenre of crime and action films that emerged in Italy in the late 1960s and reached the height of their popularity in the 1970s. They are also known as polizieschi all'italiana, Euro-crime, Italo-crime, spaghetti crime films, or simply Italian crime films. Influenced by both 1970s French crime films and gritty 1960s and 1970s American cop films and vigilante films, poliziotteschi films were made amidst an atmosphere of socio-political turmoil in Italy known as Years of Lead and increasing Italian crime rates. The films generally featured graphic and brutal violence, organized crime, car chases, vigilantism, heists, gunfights, and corruption up to the highest levels. The protagonists were generally tough working class loners, willing to act outside a corrupt or overly bureaucratic system.