The Russian Social Democratic Labour Party (RSDLP; Russian: Российская социал-демократическая рабочая партия (РСДРП), Rossiyskaya sotsial-demokraticheskaya rabochaya partiya (RSDRP)), also known as the Russian Social Democratic Workers' Party or the Russian Social Democratic Party, was a socialist political party founded in 1898 in Minsk (then part of the Russian Empire, present-day Belarus).

Formed to unite the various revolutionary organizations of the Russian Empire into one party, the RSDLP split in 1903 into Bolsheviks ("majority") and Mensheviks ("minority") factions, with the Bolshevik faction eventually becoming the Communist Party of the Soviet Union. The Interdistrictites, known as the Russian Social Democratic Labor Party (Internationalists), also formed (1913) from this party.