No. 11 Group was first formed on 1 April 1918 in No. 2 Area , and was transferred to South-Western Area the next month on 8 May. Its short first existence came to an end on 17 May when it was disbanded. Its next incarnation was later the same year when it was formed in North-Western Area on 22 August. Two years later, in May 1920, No. 11 Group was reduced to No. 11 Wing .

Its most famous period began in 1936 in RAF Fighter Command as the first Fighter command Group formed (on 14 July). As this Group was responsible for the air defense of South-West England and London, this group suffered the brunt of the German aerial assault that came to be known as the Battle of Britain.

11 Group during this time was commanded by Air Vice Marshal Keith Park, and from his Group Headquarters in Uxbridge, he directed the defense of Britain.

While fully supported by the Commanders (AOC's) of 10 Group and 13 Group, he only received luke-warm support from the AOC of 12 Group, Air Vice Marshal Trafford Leigh-Mallory, who wanted the 11 Group AOC position. This jealousy caused not a few problems for Park, and when the Battle of Britain was finally over, Leigh-Mallory, in collusion with Air Marshal Sholto Douglas, managed to have Park removed from his position (along with the Commander-In- Chief of Fighter Command, Air Chief Marshal Hugh Dowding). Leigh-Mallory then took over 11 Group.

11 Group throughout the war played the major role for Fighter Command. Pilots posted to squadrons in 11 Group knew that they would be sent into certain action while pilots and squadrons transferring out of 11 Group knew that they were going to comparatively safer duty.

Following the war 11 Group continued to be a key formation within Fighter Command. However, in 1960 there was a rationalisation of Fighter Command, and 11 Group was disbanded. However, it reformed later the same year when No. 13 Group was renamed to No. 11 Group. On 1 April 1963 the Group was renamed No. 11 (Northern) Sector. This incarnation lasted until Fighter Command was absorbed into the new Strike Command in 1968.

11 Group lasted until 1996, when it was amalgamated with No. 18 Group to form No. 11/18 Group.