Royal Air Force Flowerdown, or more simply RAF Flowerdown, is a former Royal Air Force station located in Hampshire, England.

From April 1926 the Electrical and Wireless School, part of 23 Group, Inland Area, was located at Flowerdown.

During the Second World War, Flowerdown was one of a number of listening stations around the country that fed information into Bletchley Park with staff working 12-hour shifts listening to Morse code which was then used to decipher the German codes.

In 1956 the site was taken over by GCHQ's Composite Signals Organisation as a large HF listening station.

[3] The barracks went on to become the home of the Army Training Regiment, Winchester.