They struck at Brampton Ellis School, on Brampton Road, West Melton, Rotherham, in the early hours of Friday, March 22.
Three crooks smashed a window to gain entry to the school and injected expandable foam into the burglar alarm boxes in a bid to silence them.
It is thought the offenders were attempting to steal a safe from inside the school building.
PC Brett Thompson said: “So much damage was caused during the incident that the school had to remain closed on Friday.
“This caused significant inconvenience to staff and parents who had to make alternative arrangements to care for children who should have been at school.”
Anyone with information should call South Yorkshire Police on 101 and quote incident 28 of March 22.
Crimestoppers can also be contacted, anonymously, on 0800 555 111.