They were being sold at a stall to raise funds for an orphanage in Thailand, where the school hopes to send 20 of its pupils to help with the project.
Parents at the 600-pupil school for 11 to 17-year-olds criticised the school for acting irresponsibly considering the current climate of knife crime. There have been more than 3,000 stabbings committed in Southwark since April.
One parent said: "Knives are such a problem in Camberwell and it was disgusting seeing a school selling them."
Superintendent Dave Chinchen of Southwark police said: "It's important that we all recognise, as parents and staff, the appropriateness of knives and selling them in these situations."
Headteacher Sally Coates apologised and said the sale had been "thoughtless", adding: "It was obviously a bit inappropriate, but it was done in good faith."
A spokesman for Southwark council said the school would not be selling the items in future.