It happened on the 400 block of South 16th street at 5:40 p.m.
A police unit in the area heard gunfire almost simultaneously as ShotSpotter - gunshot detection and location technology - detected gunshots.
Officers arrived to the scene where they found the boy with a gunshot wound in his leg.
The child was taken to UMDNJ for treatment of the non-life-threatening injury.
Police were still trying to determine who shot the boy and why.
Investigators are asking anyone with information about the shooting to call the Department's 24-hour Crime Stoppers anonymous tip line at 877 NWK-TIPS (877 695-8477) or NWK-GUNS (877 695-4867).