The Supermarine Walrus is a British single-engine amphibious biplane designed by Supermarine's R. J. Mitchell. Primarily used as a maritime patrol aircraft, it was the first British squadron-service aircraft to incorporate an undercarriage that was fully retractable, enclosed crew accommodation, and a fuselage completely made of metal.

Supermarine originally named the type the Supermarine Seagull V, before changing it to the Walrus. The type first flew in 1933, its design process had begun four years earlier as a private venture. It shared its general arrangement with that of the earlier Supermarine Seagull. Having been designed to serve as a fleet spotter launched by catapult from cruisers or battleships, the aircraft was employed as a maritime patrol aircraft. Early aircraft had a metal hull for greater longevity in tropical conditions, while the later variant, the Supermarine Walrus II, had a wooden hull to conserve the use of light alloys.