126 Heavy Anti-Aircraft Regiment RA (TA) was formed at Dowling, Dunbartonshire in July 1941. It served in Anti-Aircraft Command for its entire war. 126 Heavy Anti-Aircraft Regiment RA (TA) was disbanded in December 1945 at Tendring, Clacton on Sea, Essex.
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.
| Jul 41 | Formed | Dunbartonshire, UK | |
| Jul 41 |  |
5 Anti-Aircraft Division, 35 Anti-Aircraft Brigade | Portsmouth, Hampshire, UK |
| Jul 42 |  |
12 Anti-Aircraft Division, 42 Anti-Aircraft Brigade | Firth of Clyde, Scotland |
| Oct 42 |  |
5 Anti-Aircraft Group, 40 Anti-Aircraft Brigade | Nottinghamshire, UK |
| Jan 44 | |
2 Anti-Aircraft Group, 40 Anti-Aircraft Brigade | Southern England |
| Nov 44 | |
9 Anti-Aircraft Group, 40 Anti-Aircraft Brigade | East Anglia, UK |
Batteries
| Jul 41 | 423, 425, 426 |
| Jul 42 | 423, 425, 426, 431 |
| Feb 45 | 423, 425, 426 |