Two Clifton High School students are accused of sexually assaulting a 15-year-old in a stairwell during school hours in May.
Police say the girl waited several weeks to report the incident because she was afraid.
Police have charged 19-year-old Jaime Urbina and a 17-year-old with aggravated sexual assault, aggravated sexual contact and criminal restraint.
Urbina is held on $150,000 bail. The 17-year-old, whose name has not been released because of his age, is held at a juvenile detention center.
Superintendent Richard Tardalo told The Record newspaper officials are reviewing security at the school, which has 3,400 students.