The Invincible class was a class of light aircraft carrier operated by the Royal Navy. Three ships were constructed: HMS Invincible, HMS Illustrious and HMS Ark Royal. The vessels were built as aviation-capable anti-submarine warfare (ASW) platforms to counter the Cold War North Atlantic Soviet submarine threat, and initially embarked Sea Harrier aircraft and Sea King HAS.1 anti-submarine helicopters. With cancellation of the aircraft carriers renewal programme in the 1960s, the three ships became the replacements for Ark Royal and Eagle fleet carriers and the Centaur-class light fleet carriers, and the Royal Navy's sole class of aircraft carrier.

A light aircraft carrier, or light fleet carrier, is an aircraft carrier smaller than the standard carriers of a navy. The precise definition of the type varies by country; light carriers typically have a complement of aircraft only one-half to two-thirds the size of a full-sized fleet carrier. A light carrier was similar in concept to an escort carrier in most respects, however light carriers were intended for higher speeds to be deployed alongside fleet carriers, while escort carriers usually defended equally slow convoys and provided air support during amphibious operations.