Russia's Supreme Court designated the Christian denomination as "extremist" in 2017, liquidating and banning its nearly 400 chapters across the country.
Russia counted roughly 175,000 active believers at the time of the ban, according to the group's Russian website. Since then, raids, interrogations and jailings of adherents have occurred with some regularity.
A court in the Siberian city of Irkutsk handed out sentences of between three and seven years to the nine men, who ranged in age from 35 to 72.
Eight of the men had spent over two years in pre-trial detention prior to the sentencing, the majority of the time in solitary confinement, said the spokesman, Jarrod Lopes.
Lopes said charges were brought against the men based on secret audio recordings of worship services. Last week a different Russian court jailed a Witness for eight years after a "mole" filmed a prayer service held by videoconference.
Jehovah's Witnesses in Russia have previously claimed they were tortured by officers who raided their homes, allegations Russian officials have denied.
Religious life in Russia is dominated by the Russian Orthodox Church, which is championed by and loyal to President Vladimir Putin. Some Orthodox scholars view Jehovah's Witnesses, known for door-to-door preaching and refusing military service, as a "totalitarian sect".
At least 794 Witnesses have been criminally charged in Russia for their faith, and 128 are currently serving prison sentences, Lopes said.
(Reporting and writing by Lucy Papachristou; Editing by Mark Trevelyan)
