The Miles M.20 was a Second World War British fighter developed by Miles Aircraft in 1940. It was designed as a simple and quick-to-build "emergency fighter" alternative to the Royal Air Force's Spitfires and Hurricanes should their production become disrupted by bombing expected in the anticipated German invasion of the United Kingdom. Due to the subsequent shifting of the German bombing effort after the Battle of Britain towards British cities in what became known as The Blitz, together with the dispersal of British fighter manufacturing, the Luftwaffe's bombing of the original Spitfire and Hurricane factories did not seriously affect production, and so the M.20 proved unnecessary and the design was not pursued.

Miles was the name used between 1943 and 1947 to market the aircraft of British engineer Frederick George Miles, who, with his wife – aviator and draughtswoman Maxine "Blossom" Miles – and his brother George Herbert Miles, designed numerous light civil and military aircraft and a range of curious prototypes.