The incident occurred shortly before 8 p.m. on October 29.
Click here to watch the surveillance video
Authorities say the 17-year-old boy was walking on Germantown Avenue near Hortter Street when he was approached by an unknown man who asked him for a cigarette.
The suspect then pointed a handgun at the victim and demanded his belongings.
The robber stole $48 and struck the teen in the face with his gun, telling him to run away or he would get shot.
Police say the suspect fled in a small, white vehicle with a sunroof and damage to the right rear fender. He was last seen heading north on Germantown Avenue then east on Springer Street.
There were no injuries reported during this incident.
The suspect is described as a back male, 22 years-old,, 6'0" tall with a thin build, nappy beard and dark complexion. He was wearing a blue hooded sweatshirt, black pants, and armed with a handgun.
If you recognize this suspect, call police at 215.686.TIPS (8477) or text a tip to PPD TIP (773847).