Vandals went on the rampage at the Bartholomew School in Eynsham, smashing 80 windows and causing about £15,000 worth of damage.
New headteacher Andrew Hamilton said the vandalism was devastating for the school and wider community, and appealed for anyone with information to come forward.
The vandals struck on May 21, smashing almost every ground floor window of the school's main building and tower block.
Thames Valley Police said it was thought the vandals may have used goalposts from the school's playing field to carry out the attack.
Mr Hamilton, who joined the Witney Road school from the Cooper School in Bicester earlier this month, said: "It was absolutely mindless.
"Whoever it was systematically went round the outside of the building smashing windows for no particular reason. This was not about theft or getting into the building, but a shameful act of pure vandalism which affects the whole community. But I will not let this stop me from moving the school forward."
Mr Hamilton said the windows should all be replaced by the end of the week.
Pc James Ross, who is investigating the incident, said footage from several CCTV cameras outside the school buildings was due to be checked.
Anyone who saw people going onto the school site on Saturday night, or who has any other information, is urged to call Pc Ross on 08458 505505.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules hereComments are closed on this article