Just about every country within the British Empire contributed to the British war effort in one way or another. Like Canada, the self-governing dominions of New Zealand, Australia and South Africa sent troops to fight on the various fronts. Their participation in the war was never in question as a British declaration of war automatically meant the dominions were also at war. The level of the dominion commitment however was entirely up to each dominion. Canada and Australia both contributed five infantry divisions as well as several mounted brigades whilst New Zealand contributed a single infantry division and a mounted regiment. South Africa contributed a number of military units, most served on the African continent against German colonial forces in what is now Tanzania and did much of the fighting against the famous Lettow-Vorbeck. One unit served on the Western Front and others in the Middle East during the Palestine campaigns.

India, where self government had not been attained, a declaration of war was made by Viceroy Charles Hardinge. Though he did this without consulting the fledgling Indian government, the declaration of war was largely embraced by the Indian population and enormous numbers of volunteers came forward to fight for Britain. The Indian contribution was the largest of the colonial/dominion/imperial contingents with more the a million Indian soldiers serving overseas in all theaters of conflict from Gallipoli to France to the Middle East.