This article examines how Canadian Liberals understood Canada’s international relations in the late nineteenth and early twentieth centuries, situating their political thought within the British imperial world and their views of the Great War in a broader historical context. It argues that while Liberals regarded Canadian participation in the war as an affirmation of nationhood, they nonetheless conceived of Canada as a “British nation” and an integral part of a British imperial community in international politics. The article further illuminates the growth of an autonomous Canadian foreign policy within the British Empire, and shows that even the staunchest Liberal proponents of independence upheld the Dominion’s British connection. In so doing, it connects the history of Canadian Liberalism to a wider British Liberal tradition that advocated the transformation of the relationship between the United Kingdom and its settler Dominions from one of imperial dependence to that of equal, sovereign, and freely associated nations.