3 Medium Brigade was re-designated 3 Medium Regiment RA in May 1938. It was re-organised with two batteries in February 1939. In April 1947 3 Medium Regiment RA was re-designated 15 Medium Regiment RA.
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.
| 3 Sep 39 |  |
Southern Command | Larkhill, Wiltshire, UK |
| Oct 39 |  |
1 Corps | France |
| Jun 40 | Home Forces | UK | |
| May 43 |  |
Middle East Forces | N Africa |
| Jul 44 |  |
8 Army | Italy |
| May 45 |  |
2 Army | NW Europe |
Batteries
| Sep 39 | 2/11, 6/10 |
Equipment
| Sep 39 | 6 inch Howitzer |