Three fire appliances from Baschurch and Oswestry were scrambled to Adcote School, in Little Ness, Nesscliffe at 9.19pm on Wednesday.
An operations officer was also on the scene.
Crews donned breathing apparatus and used a dry powder extinguisher and a hosereel jet to deal with the flames. A positive pressure ventilation system was used to clear the smoke.
A spokesman for Shropshire Fire & Rescue Service said it was a "fire involving toaster in a common room".
The crews sent their incident stop message at 10.03pm.