Alexei Gaskarov and Alexander Margolin were sentenced to three and a half years in a prison colony, while Ilya Gushchin received two and a half years.
Yelena Kokhtareva was given a three-year-and-three-month suspended sentence.
The court had found the Kremlin critics guilty of inciting mass riots.
About 400 people were arrested at the violent protest in Moscow’s Bolotnaya Square on May 6, 2012. Authorities opened 29 cases against those arrested, with many receiving long prison terms.
Critics have denounced the trials as politically motivated.
Several demonstrators protesting outside the courthouse on Monday were arrested.