It happened around 11:45 Saturday night at the BP station on West Hunting Park and Germantown avenues.
Officials say the victim was attending a party at a nearby banquet hall when he left to go to the gas station.
While inside, the teen had a verbal confrontation with an unknown male.
The victim told police he thought the altercation was going to turn physical so he raised his hands to fight. As he did, the unidentified suspect allegedly reached for his waistband and the victim started to run.
While fleeing, the teenager heard two gunshots and was shot once in the back. He was taken to Temple University Hospital in stable condition.
The suspect is described as a black male, 18-20-years-old, approximately 6'1" tall. He has dyed blonde hair, and a Phillies "P" surrounded by a star tattooed on the front of his neck.