Casey Crime Investigation Unit detectives have charged a teenager following an alleged carjacking at Berwick College on 29 April.
It is understood the teenager, who was allegedly armed with a knife, approached a female teacher in a carpark and made demands for her car keys about 8.35am.
The teenager allegedly fled in a silver Ford Focus after the teacher handed over the keys and was left unharmed.
Detectives have arrested a 15-year-old girl in Frankston, where the Ford Focus was also located.
She has been charged with aggravated carjacking, and will appear before a children’s court at a later date.
The Department of Education spokesperson said “the safety of students and staff is our top priority – there is no place for violence or weapons of any kind at our schools.“
“Well-being supports are available for students and staff impacted by this incident.”