Police have charged a 16-year-old boy with sexually assaulting and stabbing an 18-year-old woman at a Windsor Gardens school in Adelaide's northeast.
Just after 3.30pm on Wednesday police were called to a college on Sudholz Road at Windsor Gardens after reports of an assault.
Police say the 18-year-old victim was indecently assaulted by the suspect who further assaulted her with a box cutter and scissors.
She received numerous cuts to her abdomen, lower left leg and throat and was taken by ambulance to the Royal Adelaide Hospital in a serious condition.
A 16-year-old boy from Salisbury North was arrested and charged with causing harm to another and indecent assault.
He was granted police bail to appear in the Adelaide Youth Court on September 30.
The attack at the Windsor Gardens school followed another on Tuesday, when a student was stabbed with a pair of scissors at a school in Adelaide's CBD.
The victim sustained minor injuries and was treated at the school.
A 13-year-old boy has been charged with aggravated assault, common assault and carrying an offensive weapon.