The Siberian intervention or Siberian expedition of 1918–1922 was the dispatch of troops of the Entente powers to the Russian Maritime Provinces as part of a larger effort by the western powers, Japan, and China to support White Russian forces and the Czechoslovak Legion against Soviet Russia and its allies during the Russian Civil War. The Imperial Japanese Army continued to occupy Siberia even after other Allied forces withdrew in 1920.

The Russian Civil War was a multi-party civil war in the former Russian Empire sparked by the overthrowing of the social-democratic Russian Provisional Government in the October Revolution, as many factions vied to determine Russia's political future. It resulted in the formation of the Russian Socialist Federative Soviet Republic and later the Soviet Union in most of its territory. Its finale marked the end of the Russian Revolution, which was one of the key events of the 20th century.