The Viipuri massacre was the killing of approximately 360 to 420 Russians in the city of Viipuri during the Finnish Civil War in April–May 1918. The massacre took place during and after the Battle of Viipuri as the White Guards captured the city from the Red Guards. At least half of the victims were Russian soldiers and military personnel. The slain were mainly men and young boys: nine out of ten were men fit for military service. The White Guards were "cleansing" the city of Red Guards, however, only a small minority of the killed Russians were affiliated with the Finnish labour movement.

Vyborg is a town and the administrative center of Vyborgsky District in Leningrad Oblast, Russia. It lies on the Karelian Isthmus near the head of Vyborg Bay, 130 km northwest of St. Petersburg, 245 km east of the Finnish capital Helsinki, and 38 km south of Russia's border with Finland, where the Saimaa Canal enters the Gulf of Finland. The most recent census population of Vyborg is 72,530 (2021 Census).