Officers were called to the Philadelphia Electrical and Technical Charter High School at 1420 Chestnut St in Center City around 12:30 p.m. on Wednesday.
The circumstances of the theft were not immediately disclosed.
The man who stole the computers was described as wearing a "Spectra Guard" jacket, which may have black fur on it.
He is described as an older black man with a light complexion wearing glasses, black pants and black sneakers with white soles.
