As highlighted in the recent controversies over European immigrants and the refugee ‘crisis’ that culminated in Brexit, Labour’s struggle in balancing its internationalist principles with policy administration has been a constant theme in the party’s immigration and refugee policy. This article situates the Labour Party’s discussion on the 1919 Aliens Act in the context of post-war internationalism, and contends that the change in focus from pre-war advocacy of the British liberal tradition to internationalist concerns reflected both the socialist proclamation of the Labour Party and the liberal internationalism of the time. The 1919 Aliens Act was deemed an example of selfish nationalism likely to undermine international peace and workers’ solidarity. At the same time, however, Labour also sought to shake off the suspicion that advocacy of free immigration could pose – that the party prioritized foreigners over Britons – by reconciling internationalism with patriotism. Insisting that true internationalism be built upon love of one’s home country, Labour politicians did not give up their patriotic and national claims, and accepted that a state could restrict the inflow of foreigners in times of national difficulty.