The M68 is an American 105 mm tank gun. It uses British-designed L7 gun tube and cartridges with an American-designed mount, breech assembly and recoil mechanism.

The Royal Ordnance L7, officially designated Gun, 105 mm, Tank, L7, is the basic model of the United Kingdom's most successful tank gun. It is a 105 mm L/52 rifled design by the Royal Ordnance Factories, intended for use in armoured fighting vehicles, replacing the older QF 20-pounder (84 mm) gun mounted on the British Centurion tank. The successful L7 gun has been fitted on many armoured vehicles, including the Centurion, the German Leopard 1 and, in an altered design, as the M68 gun in several variants of the US M48 Patton and M60.