Ms. Kolyada, 37, and her husband, Nikolai Khalezin, 46, founded the Belarus Free Theater in 2005, almost as an act of desperation. The nonprofit art gallery Mr. Khalezin once ran had been forced to fold under official pressure, and though he subsequently found work as a journalist, the three opposition newspapers that hired him were shut down, one after another.

“By 2004, I was so tired of politics that I began writing plays,” he said. In the meantime, Ms. Kolyada, whose academic background is in history and business, had drawn government scrutiny because of her involvement in efforts to rid Belarus of nuclear missiles, rocket fuel and other weaponry left over from the Soviet era.

“Theater was the only medium not under complete state control, because ever since Soviet times the theater has been self-censored, from inside,” explained Mr. Shcherban, who has directed most of the troupe’s productions. “That’s how we managed to surprise the K.G.B.”

But that initial advantage evaporated quickly. The Ministry of Culture soon classified Mr. Khalezin’s plays, including “Generation Jeans,” a meditation on imprisonment for nonconformity that was performed at Under the Radar in 2008, as “not recommended for production,” and also refused to allow the troupe to incorporate or register, which made it ineligible for official or even private donations.

Simultaneously, the state security apparatus undertook a campaign of intimidation and repression against cast members and even ordinary theatergoers. Some actors were fired from their day jobs at universities or other state entities, while others have been pressured through threats to their relatives; Ms. Kolyada said that her father, a well-known acting coach, lost work because of her activities.

Actors who belong to the official system “come all the time to watch us perform and tell us how much they would love to perform with us,” said Mr. Shcherban, 35. “But then they add that if they do that, they won’t be able to eat or buy an apartment.”