Around 1,400 children at Woodmill High in Dunfermline have been told to stay home for the rest of the week following the blaze on Sunday evening.
At its height, more than 80 firefighters and 15 appliances were fighting the “large and complex” fire, after it spread from an annexe, home to the school’s additional support needs department and dining hall, to the main building.
Police Scotland said a 14-year-old boy had been arrested in connection with the blaze, which it is treating as suspicious He is due to appear at Dunfermline Sheriff Court tomorrow.
It is understood Fife Council is liaising with neighbouring local authorities over how best to accommodate pupils.
The school’s head teacher said although it was too soon to determine the extent of the damage to the campus, it was “clearly extensive”.
Sandy McIntosh said: “Based on the information we have at the moment, pupils will not be able to return to school this week. We understand this is very disruptive for families – we’re investigating all our options and will keep parents, pupils and staff updated as we progress.
“Teachers are working on ways to help pupils continue with their study from home and will be in touch soon.”