The Ukrainian Canadian internment was part of the confinement of "enemy aliens" in Canada during and for two years after the end of the First World War, lasting from 1914 to 1920, under the terms of the War Measures Act.
Canada was at war with Austria-Hungary and about 4,000 Ukrainian men and some women and children of Austro-Hungarian citizenship were kept in twenty-four internment camps and related work sites – also known, at the time, as concentration camps. Their savings were confiscated until they were released. Almost all were paroled from camps in 1916–17 to become paid workers on farms, mines and railways, where labour was scarce. Another 80,000 were left at large but were registered as "enemy aliens" and obliged to regularly report to the police.
Most of the 8,600 people interned were young men apprehended while trying to cross the border into the U.S. to look for jobs; attempting to leave Canada was illegal. During the First World War, a growing sentiment against "enemy aliens" had manifested itself amongst Canadians. The British government urged Canada not to act indiscriminately against subject nationalities of the Austro-Hungarian Empire who were in fact friendly to the British Empire. However, Ottawa took a hard line. These enemy-born citizens were treated as social pariahs, and many lost their employment. Under the 1914 War Measures Act, "aliens of enemy nationality" were compelled to register with authorities. About 70,000 Ukrainians from Austria-Hungary fell under this description. 8,579 males and some women and children were interned by the Canadian Government, including 5,954 Austro-Hungarians, most of whom were probably ethnic Ukrainians. Most of the interned were poor or unemployed single men, although 81 women and 156 children (mainly Germans in Vernon and Ukrainians at Spirit Lake) had no choice but to accompany their menfolk to two of the camps, in Spirit Lake, near Amos, Quebec, and Vernon, British Columbia. Some of the internees were Canadian-born and others were naturalized British subjects, although most were recent immigrants. Citizens of the Russian Empire were generally not interned.