The 80-year-old Byre Theatre in St Andrews has closed and administrators are to be appointed. The board has been struggling to cover the costs of the venue, which had a £5.5 million facelift in 2001.
However, supporters took to Facebook and a Save the Byre page has attracted around 4000 supporters. These include River City star Tom Urie, who said he was devastated when he heard the theatre was to close.
Urie, whose first job as a professional actor was at the venue, said: "I couldn't believe it. When I was there, it was very locally run; there was a family atmosphere, but they were producing amazing stuff. There was a great audience for the place and still is. The Byre has a place in Scotland's theatre heart.
"Four thousand people have said in two days, 'we want this theatre open'."
Newsnight presenter Kirsty Wark called the decision a bad day for drama.
The online campaign was started by local artist Gillian Gamble.
"Sometimes you need a bit of grassroots pressure to make the people who can make decisions take a little bit of notice," she said. "People need a high-quality place for arts and the fact we have one already makes me think it should be used."
The board said in a statement: "The Byre has struggled to cover its costs ever since the new building opened and the problem became acute when the annual grant it had received from the former Scottish Arts Council ended in 2011."