Rocks have been used to smash windows at a school in Altwood Road in Maidenhead.
Three windows in the gym were broken sometime between Saturday and yesterday, a police community messaging alert said.
It did not say which school was targeted.
The alarm code entry system to the building was also smashed, but no-one went inside.Contact 101 or Crimestoppers on 0800 555111 with information.
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Police officers can be seen at Ten Pin Bowling in Maidenhead tonight following an incident earlier today.