Injuries to staff cost another $4.4m, compared with $4.6m in 2010, but the number of claims fell from 7534 in 2010 to 3312 last year.
ACC rehabilitation practice manager Christine Bloomfield said the type and severity of the injury and the support provided by the corporation affected the cost of the claims.
The single biggest cause of injury to pupils was a loss of balance or control, resulting in 17,150 claims.
More than 7000 pupils were injured after hitting or being knocked over by an object. Being struck by a person or an animal resulted in 6838 injuries, and 5107 pupils tripped or stumbled.
Four pupils suffered electric shocks, 21 were hurt by fire and 12 were injured by an explosion, blast or implosion.
Five pupils were hurt after eating fungi, 41 pupils had something give way under them, 53 were exposed to the elements and 397 were hurt when a stack or bulk goods collapsed on them.
Twenty-six staff and 289 pupils were hospitalised, but most injuries (42,785 pupils and 2059 staff) were treated by a general practitioner.
The single biggest cause of injury to staff was lifting or straining, with 702 claims, followed by loss of balance, which affected 336 people, and 303 staff were hurt after slipping.
Canterbury-Westland Secondary Principals' Association chairman Neil Wilkinson said schools were doing as much as they could to prevent injuries, and staff were more safety conscious.
"I'd hate to see schools become so sanitised that kids cannot play, and kids need to be kids," he said.
The most costly single injury to a pupil was $33,414 and the most costly single injury to a worker at school was $71,491.
The ACC declined to reveal what the injuries were.
