Belarusian opposition leader Svetlana Tikhanovskaya was sentenced to 15 years in absentia.
This was reported by the Belarusian agency Belta.
Prosecutors had asked for a 19-year sentence for the former presidential candidate.
The same request was made for former Culture Minister Pavel Latushko, while 12 years each were requested for three other opponents: Maria Moroz, former head of the Tikhanovskaya electoral office, Olga Kovalkova and Serghei Dylevsky.
The allegations refer to the 2020 protests against Alexander Lukashenko's re-election to the presidency after a consultation that the opposition believes is tainted by gross fraud.
Tikhanovskaya, who lives abroad like Latushko, had declared herself the winner of the presidential elections, while according to official data she had collected just over 10% of the votes.
All defendants are charged with conspiracy to seize power unconstitutionally. Tikhanovskaya is also charged with treason against the state.