The incident happened last Tuesday around 8:20 p.m. in front of 180 W. 167 St. in High Bridge.
Police say the boy was approached by the trio. One of them displayed a firearm while the others forcibly removed the boy’s sweatshirt and backpack before fleeing on foot, police say.
Anyone with information is asked to call the NYPD's Crime Stoppers Hotline at 1-800-577-TIPS (8477). The public can also submit their tips by logging onto the CrimeStoppers website.