91 Light Anti-Aircraft Regiment RA was formed in November 1941 by conversion of 12th Battalion The South Staffordshire Regiment, with three batteries . It was assigned to 4 Infantry Division in January 1942 and stayed with them until disbandment. The Regiment moved to Tunisia in March 1943 where they took part in the final stages of the campaign. The Division stayed in Tunisia while the invasions of Sicily and Italy took place. It then went to Italy in February 1944. 91 Light Anti-Aircraft Regiment RA was disbanded in December 1945 .
Illustrations of the formation badges under which a unit served or supported are given. This is no guarantee that the unit used this formations badge.
| Nov 41 | Formed from 12th Battalion South Staffordshire Regiment | ||
| Nov 41 | Home Forces | UK | |
| Jan 42 |  |
4 Infantry Division | UK |
| Mar 43 | |
4 Infantry Division | Oued Zarga, Tunisia |
| May 43 | |
4 Infantry Division | Tunis, Tunisia |
| Dec 43 | |
4 Infantry Division | Egypt |
| Feb 44 | |
4 Infantry Division | Italy |
| Apr 44 | |
4 Infantry Division | Cassino, Italy |
| Jun 44 | |
4 Infantry Division | Trasimene Line, Italy |
| Jul 44 | |
4 Infantry Division | Florence, Italy |
| Oct 44 | |
4 Infantry Division | River Savio, Italy |
| Dec 44 | Disbanded |
Batteries
| Nov 41 | 314, 315, 316 |