103 Anti-Aircraft Regiment RA(TA) was formed at Oswestry in May 1940. It was re-designated as 103 Heavy Anti-Aircraft Regiment RA(TA) in June 1940. The Regiment was disbanded in November 1945.
| May 40 | Formed | Oswestry, Shropshire, UK |
| May 40 | 33 Anti-Aircraft Brigade, 4 Anti-Aircraft Division | Liverpool, Merseyside, UK |
| Apr 42 | 65 Anti-Aircraft Brigade, 8 Anti-Aircraft Division | St Ives, Cornwall, UK |
| Nov 42 | Anti-Aircraft Command | Hertford, Hertfordshire, UK |
| Dec 42 | 76 Anti-Aircraft Brigade | Blandford, Dorset, UK |
| Apr 43 | 80 Anti-Aircraft Brigade | Blandford, Dorset, UK |
| Dec 43 | 80 Anti-Aircraft Brigade | Renfrewshire, UK |
| Apr 44 | 80 Anti-Aircraft Brigade | Mannings Heath, Sussex, UK |
| Jun 44 | N Anti-Aircraft Assault Group | Sword Beach, Normandy, France |
| Sep 44 | 80 Anti-Aircraft Brigade | Dieppe, France |
| Oct 44 | 103 Anti-Aircraft Brigade | Boulogne, France |
| Nov 44 | 101 Anti-Aircraft Brigade | Brussels, Belgium |
| Dec 44 | 105 Anti-Aircraft Brigade | Knokke, Belgium |
| Apr 45 | Converted to driver training unit | Hoogerheide, Holland |
Batteries
| May 40 | 322, 323, 324 |
| July 41 | 322, 323, 324, 420 |
| Apr 42 | 322, 323, 324 |
