Il Marchese del Grillo is a 1981 Italian comedic motion picture directed by Mario Monicelli, starring Alberto Sordi as the title character. The film depicts early nineteenth-century episodes in the life of a nobleman in Rome. Loosely based on folkloric accounts of the real Onofrio del Grillo, this character plays a number of pranks, one even involving Pope Pius VII. The famous line Io sò io, e voi non siete un cazzo, is appropriated from Belli's 1831 sonnet, "The Sovrans of the Old World".

Mario Alberto Ettore Monicelli was an Italian film director and screenwriter, one of the masters of the commedia all'italiana. He was nominated six times for an Oscar, and received the Golden Lion for his career.