No. 640 Squadron RAF was a heavy bomber squadron of the Royal Air Force during the Second World War.
No. 640 Squadron was first formed at RAF Leconfield, East Riding of Yorkshire on 7 January 1944, from 'C' Flight of No. 158 Squadron RAF. It was equipped with Halifax Mk.III bombers, and operated as part of No. 4 Group in Bomber Command. It re-equipped with Halifax VI bombers in March 1945, and was disbanded at RAF Leconfield on 7 May of that year.