Hours after the Outram School Parent Teachers Association discussed beefing up security, the school was targeted by thieves who stole $20,000 worth of equipment.
Principal Greg Carroll said the thieves' actions had hurt the pupils, teachers and wider community.
"It is immensely frustrating for us."
The theft had occurred after the PTA had finished discussing various school issues, including security, he said.
As a result, the school's alarm system would be extended to include the classroom block where the burglary took place.
During Mr Carroll's four-year tenure the school had been broken into twice before, with the latest incident appearing more professional than opportunistic.
The thieves took three 106cm LCD televisions, five Mac laptops, one PC laptop, two stereo systems, a digital camera and a desktop iMac computer.
All the items were insured, and would be replaced as soon as possible.
"We feel violated from this. They have taken things that are important for learning."
One teacher, Tania Bellamy, lost her white Macbook laptop in the break-in, and said she would offer a reward for its safe return to the school or police.
"It's just got basically my whole life - information, research, everything - on it."
Mr Carroll said he addressed a special assembly of the 240 pupils yesterday, in which he assured them the school was still a safe place to be.
Mosgiel police are investigating the incident.
