A government-run school in Narendrapur in southern fringes of the city was allegedly attacked and around Rs 40,000 was robbed, police said on Monday.
The incident happened in Nayabad High School in Narendrapur police station area, they said.
Around 10 cupboards were broken open and the money was looted, officials said.
The school authorities alleged that a number of important documents have also gone missing.
Police said they are investigating the matter and no arrests have yet been made.