Principal David Grant said the school grounds were looked after by its pupils and members of the Brighton coast community.
"It's as much a necessity as anything. We don't have a caretaker because the school is so small and it's not economically viable to employ one.
"This gives the kids ownership of the school - they really care about the place. There have been occasions when the kids have told visitors to take more care and look after their school.
"They tell them to use rubbish bins - simple stuff like that."
Mr Grant said he had noticed a significant decline in vandalism at the school since the pupils started doing garden work, rubbish collection and simple playground maintenance.
Big Rock School was one of 42 schools across the city to enter the Keep Dunedin Beautiful Best Caretaker Award.
The award was won last week by Balaclava School caretaker Graham Hansen.
But Keep Dunedin Beautiful co-ordinator Darlene Thomson was so impressed with Big Rock School, she decided to create a special award to reward pupils for their hard work.
"We were amazed that of the 42 nominations, Big Rock School was the only one to do the work themselves."
The school was officially presented with the award yesterday.
