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501 squadron was formed in 1929 as a Special Reserve unit with day bomber duties. In 1936 the squadron was transferred to the Auxiliary Air Force and was converted to a fighter unit two years later. The squadron was equipped with Hurricanes in March 1939 and in May 1940 flew fighter cover for the Advanced Air Striking Force in France. The squadron was based in the south throughout the Battle of Britain, flying variously from Croydon, Middle Wallop, Gravesend and Kenley.

The squadron was disbanded in the 1950s. Some fifty years later it was reformed, in 2001, at RAF Brize Norton, as a Force Protection unit and part of the Royal Auxiliary Air Force.