The Vickers K machine gun, known as the Vickers Gas Operated or Gun, Machine, Vickers G.O. .303-inch in British service, was a rapid-firing machine gun developed and manufactured for use in aircraft by Vickers-Armstrongs. The high rate of fire was needed for the short period of time when the gunner would be able to fire at an attacking aircraft. The weapon was adopted for land use during World War II.

Vickers-Armstrongs Limited was a British engineering conglomerate formed by the merger of the assets of Vickers Limited and Sir W G Armstrong Whitworth & Company in 1927. The majority of the company was nationalised in the 1960s and 1970s, with the remainder being divested as Vickers plc in 1977.