It happened around 9:15 a.m. Wednesday at Philadelphia Learning Academy - North on the 4200 block of North Front Street.
Police say the victim suffered superficial stab wounds on his left arm and was treated by medics.
The 14-year-old suspect was taken into custody and the weapon was recovered.
The school was initially placed on lockdown but it has since been lifted.
The school district said the student was injured with scissors.