When did Canada fight in war to support the British Empire?

Question

It was when Canada had nothing to do with the conflict but had to fight for the British Empire since it was a part of it...

Answer 1

Canada was automatically at war in August of 1914, when Britain declared war on Germany.

In 1939, Canada declared war separately, on September 9th. (Prime Minister Mackenzie King -- who was mad -- waited untill both hands on the clock were pointing up to actually issue the declaration of war.)

During the Boer War, Canadians served as volunteers, and were trained and equipped by the government, but the Canadian government did not actually particpate in the war effort.

Answer 2

The first answer is very good. There were a couple of other wars, War of 1812, King George's War where the colonies fought each other (1740–1748), and the 7 year's war (French and English colonies fought each other (1756-1763).