The Gloster Javelin was a twin-engined all-weather interceptor aircraft that served with Britain's Royal Air Force in the late 1950s and most of the 1960s. It was a T-tailed delta-wing aircraft designed for night and all-weather operations and was the last aircraft design to bear the Gloster name. Introduced in 1956 after a lengthy development period, the aircraft received several upgrades during production to its engines, radar and weapons, including support for the De Havilland Firestreak air-to-air missile.

The Javelin was succeeded in the interceptor role by the English Electric Lightning, a supersonic aircraft capable of flying at more than double the Javelin's top speed, which was introduced into the RAF only a few years later. The Javelin served for much of its life alongside the Lightning; the last Javelins were withdrawn from operational service in 1968 following the induction of successively more capable versions of the Lightning.