Crawley firefighters were called to a school fire this afternoon (Thursday March 20).
More than 30 firefighters were tackling the blaze at Millais School, Horsham.
The fire was reported at 2.52pm on the 3rd floor of the 3-storey building.
All staff and pupils were safely evacuated prior to the arrival of fire crews.
No injuries had been reported.
Firefighters were at the scene within seven minutes of the alarm being raised.
Four additional crews were immediately requested after smoke was seen issuing from the roof.
Crews are fighting the fire using eight breathing apparatus wearers, six jets as well as an aerial ladder platform so the blaze can be tackled from above.
Depot Road is currently closed between the junction with Orchard Road to the west and Comptons Lane to the east.
Police were advising parents wishing to collect their children to do so via Highlands Road to the south of the school.
The cause of the fire is currently under investigation.