NSW Ambulance paramedics treated a 22-year-old man at the scene. He was taken to Royal Prince Alfred Hospital in a serious but stable condition.
Multiple university building were sent into lockdown as police established a crime scene.
A short time later police were told the 14-year-old had left the scene after the alleged stabbing, boarding a bus on Parramatta Road.
He was later found by police near Royal Prince Alfred Hospital, where he was arrested.
A NSW Police spokesperson said the teenager and the alleged victim were not known to each other, and there is no ongoing risk to the public.
