The Group of Democratic Centralism (Russian: Группа демократического централизма, romanized: Gruppa demokraticheskogo tsentralizma), sometimes called the Group of 15, the Decists, or the Decemists (децисты, detsisti), was a dissenting faction within the Communist Party of the Soviet Union in the early 1920s.
The group's original leaders were Old Bolsheviks Valerian Obolensky-Ossinsky, Vladimir Smirnov, Timofei Sapronov, V. N. Maximovsky, M. S. Boguslavsky, A.
They were active during the intra-Party "trade union discussion" in late 1920-early 1921 when the Party split into numerous factions, but didn't gather much support and the faction became moribund after the 10th Party Congress in March 1921.
The Group's leaders continued to protest what they saw as a gradual abolition of intra-Party democracy throughout the early 1920s and joined Leon Trotsky's Left Opposition in 1923.
In 1926 Sapronov and Smirnov formed the "Group of 15", which joined the United Opposition headed by Trotsky, Grigory Zinoviev and Lev Kamenev.