Although they had made no direct contribution to the Allied victory, the Nordic countries were substantial net beneficiaries of the peace settlement. Their security had been enhanced by the destruction of Germany and Russia as great powers, apparently for the foreseeable future. The League of Nations, which derived in part from Scandinavian ideas and initiatives, offered a new approach to international security. All four countries saw the end of the war as an opportunity for territorial expansion. For Denmark, of course, it was a matter of regaining territory lost in 1864. Following a plebiscite in 1920, the northern part of Slesvig was returned to Denmark, leaving a small Danish minority to the south of the new frontier and a rather larger German minority to the north. Sweden laid claim to the Åland Islands. Having relied on German patronage in 1918, the Swedes turned in 1919 to the Paris peace conference, which then referred the question to the League of Nations. In 1921 the League decided that the islands should remain in Finnish possession but with a large measure of self-determination, and that they should also be demilitarised. Sweden was thus the only Nordic country which did not gain territorially at the end of the war; but Swedish discomfiture, though vocal for a while, was relatively short-lived.

Independent Finland sought to extend the historic frontiers of the Grand Duchy into East Karelia, the cradle of Finnish culture, and northward to the Arctic Ocean. The peacemakers gave Finland an Arctic port at Petsamo but refused to satisfy its designs on Karelia – a source of lasting resentment to Finnish nationalists.