The White Terror (Russian: Белый террор, romanized: Belyy terror) in the former Russian Empire refers to violence and mass killings carried out by the White movement and its governments of Russia during the Russian Civil War (1917–1923). Individual acts against Bolshevik rule, such as assassinations, commenced at least by the end of 1917. Violence on any sizable scale on the part of the Whites arguably began in early 1918, continuing until the defeat of the Whites at the hands of the Red Army from 1920 to 1922. Unlike in the case of the Red Terror, there was no formal decree which kickstarted the White Terror. The White Terror was most acute in the Far East, under warlords such as Grigory Semyonov and Baron Roman von Ungern-Sternberg.
Though the Bolsheviks' Red Terror officially began on September 5, 1918 in response to several planned assassinations of Bolshevik leaders, incidents of violence carried out by Bolsheviks and their supporters had been ongoing since the October Revolution. According to some Russian historians, the White Terror was a series of premeditated actions directed by their leaders; this view is contested by Russian historians who view it as spontaneous and disorganized. According to some historians, the White Terror evolved from a disorganized policy to a system of political repression sanctioned by the Russian State and its system of military dictatorship which targeted not only the Bolsheviks, but members of other parties and other people as well. Some historians believe the antisemitic pogroms carried out by the Whites to be a part of the White Terror.