Flames could be seen rising from the roof of Fort Myers High School's gym building.
According to the Fort Myers Fire Department, the fire possibly started from roof work. Fire crews were able to extinguish the flames.
FMFD said crews were able to extinguish most of it through aerial operations and aggressive attack.
Crews are assessing for any fire extension and clean-up, FMFD Chief Tracy McMillion said. There were no injuries, according to FMFD.