Obsolescent by the time the war started, the Gloster Gladiator nevertheless was hard pressed for duty due to the RAF's shortage of suitable fighter aircraft. Serving in Europe first (initially in France, later during the Battle of Britain defending the Plymouth Dockyards), it was relegated to second-line duty but used in the front-line in the Mediterranean theater, notably in the defense of Malta and in North Africa where it performed rather admirably. It was over Malta where three navalized Sea Gladiators made a valiant defense against Italian air strikes and were given the nicknames "Faith", "Hope", and "Charity". With an enclosed cockpit and cantilever landing gear, the Gladiator will be remembered as the last British biplane fighter and was also used extensively by over a dozen other nations including combat service by Belgium and Greece as well as China and Finland in the Sino-Japanese and Russo-Finnish wars.

The prototype Gladiator flew as early as September 1934 with the initial production variant being the Mk. I. The main wartime variant was the Mk. II with an uprated engine and optimized for tropical use with desert filters. A naval variant was the Sea Gladiator with catapult points and an arrester hook, initial units were conversions of Mk. I aircraft.