The fire is thought to have broken out in the sport's hall of Magdalen College School
Firefighters have battled a blaze at a historical school in Oxford.
The fire is thought to have broken out in the sport's hall of Magdalen College School at about 19:15 BST.
David Parton, a student at the adjacent St Hilda's College at the University of Oxford, said: "There was a large amount of black smoke, it was growing and the flames were clearly very visible and very large."
Thames Valley Police said no casualties had been reported.
The school and neighbouring colleges were evacuated, while the fire service searched the building.
South Central Ambulance Service was on the scene.
The fire service have searched the building
Mr Parton said: "You could see the flames through the roof, it's quite badly damaged. Tiles and guttering have fallen off. The fire spread across the side of the roof from the bottom to the top.
"It was concerning, especially when it was at its closest to our building."
Sgt Paul Roberts said officers were "working hard to keep disruption to a minimum".
The school, which opened in 1480, teaches 900 pupils aged between 7 and 18.
The cause of the fire is unknown.
University students watched the fire unfold from nearby tennis courts
The school and neighbouring colleges were evacuated
