Allied intervention in the Russian Civil War

The Allied intervention in the Russian Civil War consisted of a series of multi-national military expeditions that began in 1918. The initial impetus behind the interventions was to secure munitions and supply depots from falling into the German Empire's hands, particularly after the Bolsheviks signed the Treaty of Brest-Litovsk, and to rescue the Allied forces that had become trapped within Russia after the 1917 October Revolution. After the Armistice of 11 November 1918, the Allied plan changed to helping the White forces in the Russian Civil War. After the Whites collapsed, the Allies withdrew their forces from Russia by 1925.

Allied troops landed in Arkhangelsk (the North Russia intervention of 1918–1919) and in Vladivostok (as part of the Siberian intervention of 1918–1922). The British also intervened in the Baltic theatre (1918–1919) and in the Caucasus (1917–1919). French-led Allied forces participated in the Southern Russia intervention (1918–1919).

Allied efforts were hampered by divided objectives, war-weariness after World War I, and a rising discontent among some troops and sailors who were reluctant to fight the world's first socialist state; this reluctance sometimes led to mutiny.^{[according to who]} These factors, together with the evacuation of the Czechoslovak Legion in September 1920, led the western Allied powers to end the North Russia and Siberian interventions in 1920, though the Japanese intervention in Siberia continued until 1922 and the Empire of Japan continued to occupy the northern half of Sakhalin until 1925.