Officers responded to reports of gunfire around 8:30 pm yesterday and found Caleer Miller and Salvatore Dinubile with chest wounds. They later died at a hospital.
Police are investigating what led to the shooting.
The boys' killings mark a deadly day in a city that has failed to stem gun homicides.
There have been 253 homicides this year in the city as of yesterday, a 10 per cent increase from the same period in 2016.
Philadelphia is on track to have its deadliest year since 2012, when more than 330 people died in homicides.