Within nations occupied by the Axis powers in World War II, some citizens and organizations, prompted by nationalism, ethnic hatred, anti-communism, antisemitism, opportunism, self-defense, or often a combination, knowingly collaborated with the Axis Powers. Some of these collaborators committed war crimes, crimes against humanity, or atrocities in the Holocaust.Collaboration has been defined as cooperation between elements of the population of a defeated state and representatives of the victorious power. Stanley Hoffmann subdivided collaboration into involuntary (reluctant recognition of necessity) and voluntary (exploitation of necessity). According to Hoffmann, collaborationism can be subdivided into "servile" and "ideological"; the former is deliberate service to an enemy, whereas the latter is deliberate advocacy of cooperation with a foreign force which is seen as a champion of desirable domestic transformations. In contrast, Bertram Gordon uses the terms "collaborator" and "collaborationist", respectively, about non-ideological and ideological collaborations.

The Russian Liberation Army (German: Russische Befreiungsarmee; Russian: Русская освободительная армия, Russkaya osvoboditel'naya armiya, abbreviated as РОА, ROA, also known as the Vlasov army (Власовская армия, Vlasovskaya armiya)) was a collaborationist formation, primarily composed of Russians, that fought under German command during World War II. The army was led by Andrey Vlasov, a Red Army general who had defected, and members of the army are often referred to as Vlasovtsy (Власовцы). In 1944, it became known as the Armed Forces of the Committee for the Liberation of the Peoples of Russia (Вооружённые силы Комитета освобождения народов России, Vooruzhonnyye sily Komiteta osvobozhdeniya narodov Rossii, abbreviated as ВС КОНР, VS KONR).

Vlasov agreed to collaborate with Nazi Germany after having been captured on the Eastern Front. The soldiers under his command were mostly former Soviet prisoners of war but also included White Russian émigrés, some of whom were veterans of the anti-communist White Army from the Russian Civil War (1917–23). On 14 November 1944, it was officially renamed the Armed Forces of the Committee for the Liberation of the Peoples of Russia, with the KONR being formed as a political body to which the army pledged loyalty. On 28 January 1945, it was officially declared that the Russian divisions no longer form part of the German Army, but would directly be under the command of KONR.