The All-Union Leninist Young Communist League, was a political youth organisation in the Soviet Union. It is sometimes described as the youth division of the Communist Party of the Soviet Union (CPSU), although it was officially independent and referred to as "the helper and the reserve of the CPSU".

The Komsomol in its earliest form was established in urban centres in 1918. During the early years, it was a Russian organisation, known as the Russian Young Communist League, or RKSM. During 1922, with the unification of the USSR, it was reformed into an all-union agency, the youth division of the All-Union Communist Party.

It was the final stage of three youth organisations with members up to age 28, graduated at 14 from the Young Pioneers, and at nine from the Little Octobrists.