Police were called at 9.15am on Friday, 20 January to reports of a number of youths in possession of a knife.
Officers, including firearms officers, attended. A 13-year-old boy was found with stab injuries.
He was taken to hospital by the London Ambulance Service; his injuries are not believed to be life-threatening.
Officers remain in the area and a crime scene is in place.
At this early stage, there have been no arrests.
Anyone with information is asked to call police via 101 quoting reference CAD 1645/20Jan.