The War Measures Act (http://laws.justice.gc.ca/en/W-2/) was a Canadian statute that allowed the government to assume sweeping emergency powers. When the act was invoked, citizens could be arrested and imprisoned without the benefit of trial or even a stated explanation. It essentially created a state of martial law throughout the country.

The act was invoked three times in Canadian history: World War I, World War II, and most controversially during the October Crisis of 1970.

The act was later repealed and replaced with the Emergencies Act in 1988.