Sergei Nikiforovich Vasilenko (Russian: Серге́й Никифорович Василенко, Sergej Nikiforovič Vasilenko; 30 March 1872 [O.S. 18 March] – 11 March 1956) was a Russian and Soviet composer, conductor and music teacher whose compositions showed a strong tendency towards mysticism.

Vasilenko was born in Moscow and originally studied law at Moscow State University, but then changed direction and studied at the Moscow Conservatory from 1896 to 1901 as a pupil of Sergei Taneyev and Mikhail Ippolitov-Ivanov. From 1903 to 1904 he was the conductor of a private opera house in Moscow. For several years he was the organiser and conductor of the Historic Concerts of the Russian Musical Society. He then became a Professor at the Moscow Conservatory, where his students included Aram Khachaturian, Nikolai Roslavets, Nikolai Rakov and Aarre Merikanto.

Vasilenko was awarded two Orders of the Red Banner of Labour as well as the title People's Artist of the RSFSR. In 1947, he was awarded the Stalin Prize. He died in Moscow in 1956.