The attack took place around 11pm but it was not until around 2am that the girl, helped by people she met in the area, was able to report it to the police.
She said that she was raped by four young men behind Rinkeby school in the northwest suburb of the capital. According to police spokesman Christer Persson, the attackers are probably younger than the girl.
“The girl has given a description of them. She didn’t recognise them to the extent that she was able to name them,” he told reporters.
She was taken to hospital in the night and police will carry out forensic tests at the scene throughout the day on Tuesday.