The Gloster Gladiator is a British biplane fighter. It was used by the Royal Air Force (RAF) and the Fleet Air Arm (FAA) and was exported to a number of other air forces during the late 1930s.

A biplane is a fixed-wing aircraft with two main wings stacked one above the other. The first powered, controlled aeroplane to fly, the Wright Flyer, used a biplane wing arrangement, as did many aircraft in the early years of aviation. While a biplane wing structure has a structural advantage over a monoplane, it produces more drag than a monoplane wing. Improved structural techniques, better materials and higher speeds made the biplane configuration obsolete for most purposes by the late 1930s.