The robbery happened at about 5:50 p.m. on Wednesday, April 23.
Police say the victim was walking along the 1600 block of Tasker Street when three teenage boys and a teenage girl approached him from behind.
When the victim turned around, one of the suspects punched him in the jaw, knocked him to the ground and began kicking him.
After stealing the victim's cellphone, the suspects fled east on Tasker Street.
The victim suffered minor cuts and bruises to his head and arm.
Police describe the suspects as:
Suspect #1: Black male, 15-19 years-of-age, 5'5, 140 lbs., high box style haircut, light complected, clean shaven, multicolored jacket, and black pants.
Suspect #2: Black male, 15-19 years-of-age, 5'6, 160 lbs., wearing a gray jacket.
Suspect #3: Black male, 15-19 years-of-age, heavy set, dark complexion, carrying a book bag.
Suspect #4: Black female, 15-19 years-of-age, light complected, long black hair.
Anyone with information is asked to contact Philadelphia Police at 215.686.TIPS (8477), text a tip to PPD TIP or 773847 or submit a tip at PhillyPolice.com.