It happened around 9:17 p.m. on the 6400 block of North Broad Street inside a home.
Police say a 15-year-old boy was playing with a gun when his 14-year-old friend was shot one time in the stomach.
The victim was taken to an area hospital in serious but stable condition.
Police say the 15-year-old fled the scene after the incident.
A gun was recovered but no arrests have been made.
Anyone with information is asked to call police at 215-686-TIPS.