Police believe they know the identity of the deceased, and enquiries are underway to locate next of kin. Formal identification and a post-mortem examination will be arranged in due course.
Police were called shortly before 7pm on Sunday, 29 October, to reports of a seriously injured male in North End, Croydon.
Officers found a male aged about 17 years old, suffering serious stab injuries.
Officers gave first aid before the arrival of the London Ambulance Service, but the boy was pronounced dead at the scene.
A murder investigation has now commenced, led by officers from the Homicide and Major Crime Command working with colleagues from Croydon at the scene.
There has been no arrest at this early stage. Cordons remain in place.
Sarah Jones, MP for Croydon Central, called on Home Secretary Amber Rudd to tackle the knife crime “epidemic” as a priority.
South London, Appeals, Specialist Crime & Operations, Croydon