The Beretta M12 is a 9×19mm Parabellum caliber submachine gun designed by Beretta. Production started in 1959, the first users were the Italian Carabinieri, Italian State Police and the Guardia di Finanza, though in limited numbers; it was only widely issued beginning in 1978, replacing the old Beretta MAB. In 1962 the Italian Army bought a limited number of Franchi LF-57 submachine guns, judged better than the M12 but never issued to the troops, and only in 1992 the M12S2 variant was introduced, in very limited numbers. The Italian Air Force bought instead many M12S and M12S2 for the airport security units. However, the weapon had a higher initial success in the Arab countries and South America.

A submachine gun (SMG) is a magazine-fed automatic carbine designed to fire handgun cartridges. The term "submachine gun" was coined by John T. Thompson, the inventor of the Thompson submachine gun, to describe its design concept as an automatic firearm with notably less firepower than a machine gun. As a machine gun must fire rifle cartridges to be classified as such, submachine guns are not considered machine guns.