138 Light Anti-Aircraft Regiment RA (TA) was formed in May 1942 at Newmarket. The Regiment was disbanded in December 1945 at Braughton, Barnstaple.
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.
| May 42 | Formed from batteries from 64, 78, 79 & 96 Light Anti-Aircraft Regiments | Newmarket, Suffolk, UK | |
| Jun 42 |  |
2 Anti-Aircraft Division, 40 Anti-Aircraft Brigade | UK |
| Dec 45 | Disbanded | Barnstaple, Devon, UK |
Batteries
| May 42 | 454, 458, 469, 470 |
| Feb 44 | 454, 458, 469 |