The incident occurred just before 6:30 p.m. Thursday in front of Martin Hall, on the campus located at 1001 Eagle Road in Wayne.
Radnor police say two 13-year-old cadets got into argument, with one student stabbing the other in the leg.
The victim was taken to Bryn Mawr Hospital, where he was treated and later released.
The other student is charged with aggravated assault.
A juvenile hearing is scheduled for tomorrow morning in Lima, Delaware County for the suspect.
