The Old Bolsheviks, also called the Old Bolshevik Guard or Old Party Guard, were members of the Bolshevik faction of the Russian Social Democratic Labour Party prior to the Russian Revolution of 1917. Many Old Bolsheviks became leading politicians and bureaucrats in the Soviet Union and the ruling Communist Party. While some died over the years from natural causes, many were removed from power, imprisoned in gulags or executed in the late 1930s, as a result of the Great Purge by Joseph Stalin.

The Bolsheviks, led by Vladimir Lenin, were a far-left faction of the Marxist Russian Social Democratic Labour Party (RSDLP) which split with the Mensheviks at the Second Party Congress in 1903. The Bolshevik party seized power in Russia in the October Revolution of 1917, and was later renamed the Communist Party of the Soviet Union. Their ideology and practices, based on Leninist and later Marxist–Leninist principles, are known as Bolshevism.