It happened early Monday morning at St. Martin of Tours school on the 5700 block of Loretto Avenue.
Police say the burglar broke into the school through a front window.
Click here to watch the surveillance video
Once inside, the thief stole several laptops and computer equipment totaling over $5,000 before fleeing in an unknown direction.
The suspect is described as a white male, 18 to 22-years-old with a thin build. He was wearing a white tank top, black pants, a black hat and white sneakers.
Anyone with information on this burglary is asked to call police at 215.686.TIPS (8477) or text a tip to PPD TIP (773847).