Left communism, or the communist left, is a position held by the left wing of communism, which criticises the political ideas and practices espoused by Marxist–Leninists and social democrats. Left communists assert positions which they regard as more authentically Marxist than the views of Marxism–Leninism espoused by the Communist International after its Bolshevization by Joseph Stalin and during its second congress.

In general, there are two currents of left communism, namely the Italian and Dutch–German left. The communist left in Italy was formed during World War I in organizations like the Italian Socialist Party and the Communist Party of Italy. The Italian left considers itself to be Leninist in nature, but denounces Marxism–Leninism as a form of bourgeois opportunism materialized in the Soviet Union under Stalin. The Italian left is currently embodied in organizations such as the Internationalist Communist Party (Battaglia Comunista) and the International Communist Party. The Dutch–German left split from Vladimir Lenin prior to Stalin's rule and supports a firmly council communist and libertarian Marxist viewpoint as opposed to the Italian left which emphasised the need for an international revolutionary party.

Left communism differs from most other forms of Marxism in believing that communists should not participate in bourgeois parliaments, and some argue against participating in conservative trade unions. However, many left communists split over their criticism of the Bolsheviks. Council communists criticised the Bolsheviks for elitist party functions and emphasised a more autonomous organisation of the working class, without political parties.

Although she was murdered in 1919 before the communist left appeared as a distinct current, Rosa Luxemburg has heavily influenced most left communists. Proponents of left communism have included Amadeo Bordiga, Onorato Damen, Jacques Camatte, Herman Gorter, Antonie Pannekoek, Otto Rühle, Sylvia Pankhurst and Paul Mattick.

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