The shooting happened just after 8:30 p.m. on the 800 block of North 48th Street.
Police said the 15 year old was standing with a relative in the doorway to the living room, when the gunman walked in through an enclosed porch and started firing.
The teen was shot at least one time in the chest, police say.
Family members took the teen to Penn Presbyterian Medical Center where he remains in critical condition.
There have been no arrests have been made at this time.
Anyone with information is asked to contact the police.