The guerrilla war in the Baltic states was an insurgency waged by Baltic partisans against the Soviet Union from 1944 to 1956. Known alternatively as the "Forest Brothers", the "Brothers of the Wood" and the "Forest Friars", these partisans fought against invading Soviet forces during their occupation of the Baltic states during and after World War II. Similar insurgent groups resisted Soviet occupations in Bulgaria, Poland, Romania and Ukraine.

Lithuanian partisans were partisans who waged guerrilla warfare in Lithuania against the Soviet Union in 1944–1953. Similar anti-Soviet resistance groups, also known as Forest Brothers and cursed soldiers, fought against Soviet rule in Estonia, Latvia and Poland. An estimated total of 30,000 Lithuanian partisans and their supporters were killed. The Lithuanian partisan war lasted almost for a decade, thus becoming one of the longest partisan wars in Europe.