A Machine Gun Company of the Machine Gun Corps was attached to each Infantry Brigade and their subsequent Division. An additional Company was attached as a divisional reserve.
| Brigade attached to: | Divisional Reserve |
| Division attached to: | 15th (Scottish) Division |
The 225th M.G. Coy. formed at Grantham. It embarked at Southampton on 11 July 1917 and disembarked at le Havre on 12 July 1917. It left le Havre on 18 July 1917 and joined 15th (Scottish) Division at Brandhoek on 19 July 1917.
As a unit of the 15th (Scottish) Division, it may have taken part in the following battles and engagements.
| 1917 | |
| BATTLES OF YPRES | |
| 31 July to 02 August | Battle of Pilckem Ridge [XIX Corps, Fifth Army]. |
| 17 and 18 August | Battle of Langemarck (46th Brigade) [XIX Corps, Fifth Army]. |
| 22 August | Fighting for Zevenkote [XIX Corps, Fifth Army]. |
On 17 March 1918, it was amalgamated with the 44th, 45th and 46th Machine Gun Companies to form No. 15 Battalion, Machine Gun Corps.
