Alternative History
All-Union Communist Party
Всесою́зная Коммунисти́ческая Па́ртия
Founder Vladimir Lenin
Slogan Workers of the world, unite!
Founded January 1, 1912
Dissolved May 9, 1945
Preceded by Russian Social Democratic Labour Party
Newspaper Pravda
Youth wing Komsomol
Ideology Communism
Stalinism (1927-1945)
International affiliation Comintern
Official colours Red

The All-Union Communist Party (Russian: Всесою́зная Коммунисти́ческая Па́ртия; short: ВКП, AUCP) was the constitutional force of societal organisation in the Soviet Union and one of the largest communist organisations in the world. Following the defeat of the Soviet Union at the conclusion of World War II in Europe, the party was "completely and finally abolished and declared to be illegal" by the Axis occupying powers.

It emerged from the Bolshevik faction of the Russian Social Democratic Labour Party, under the leadership of Vladimir Lenin. The party led the 1917 October Revolution that overthrew the Russian Provisional Government and claimed to have established the world's first socialist state. Given the central role under the Constitution of the Soviet Union, the party controlled all tiers of government and social institutions in the Soviet Union. Its organization was subdivided into communist parties of the constituent Soviet republic as well as the mass youth organisation, the All-Union Leninist Young Communist League. The party was also the driving force of the Third International (Comintern).