Police Scotland are investigating a break-in at Mintlaw Academy last week.
The incident, in which a window was smashed, is believed to have occurred between 9:30pm and 10:30am on Wednesday 27 January.
Inspector Simon Reid, of the Buchan Community Policing Inspector, said: “Whether the intention was to break in and steal items or this was simply a mindless act of vandalism towards an important community facility, this is unacceptable.
“Those responsible have shown a total disregard for the impact and upset this will have caused pupils and staff, not to mention the wider community.”
Police Scotland are appealing for anyone with information to contact them on 101 or Crimestoppers on 0800 555 111 if you wish to remain anonymous.
Inspector Reid said: “Whether you saw anything suspicious or suspect you may know who is responsible, please come forward.
“Don’t assume that someone else may have already told us.”