No. 691 Squadron RAF was an Anti-aircraft cooperation squadron of the Royal Air Force from 1943 to 1949.
The squadron was formed on 1 December 1943 at RNAS Roborough from 1623 (anti-aircraft co-operation) Flight. It was tasked with anti-aircraft co-operation duties in the Plymouth area operating a variety of aircraft in this role. Most of the work was to fly as training targets for Royal Navy ships. The squadron moved a number of times from the end of the war to RAF Exeter, RAF Weston Zoyland, RAF Fairwood Common, and finally to RAF Chivenor. Its existence ended there when it was renumbered to No. 17 Squadron RAF on 11 February 1949.