An argument began on the bus and at some point she attacked a 15-year-old classmate, cutting her on the arm and face, according to school system Director of Public Information Louis Svehla.
The injuries were not life-threatening, but the girls guardians took her to Medical College of Georgia Hospital and Clinics.
The attacker was arrested later Monday at her home and taken to the Regional Youth Detention Center, Mr. Svehla said. She was also suspended pending a disciplinary tribunal hearing.
It appears some type of weapon was used in the attack, but that and other details are still being investigated, he said. Random searches were conducted today at Hephzibah High School as a precaution. Additional school board public safety officers were also on campus.