The Gloster Grouse was a British biplane of the 1920s developed by the Gloster Aircraft Company. Often referred to as the prototype to the Gloster Grebe, the Grouse originally built as an experimental aircraft and then later developed as a trainer. Despite its compact design and maneuverability, the Grouse was not in itself a commercial success, although it formed the basis for the Gloster Grebe and Gamecock fighters which were used by Britain's Royal Air Force into the 1930s.