Two boys, aged 17, were taken to the hospital after police were called to reports of a stabbing on Old Kent Road, Southwark, on Wednesday, August 27.
One of the boys, who has been named Yeray Sanchez-Morales, died on Wednesday, the Metropolitan Police said.
The second victim has since been discharged from the hospital.
A 15-year-old boy, who cannot be named for legal reasons, was arrested on suspicion of attempted murder on September 1.
On Thursday, he was charged with murder, grievous bodily harm, and possession of an offensive weapon, the force said.
He will appear at Bromley Magistrates’ Court on Thursday afternoon.
’Unimaginably difficult’
Detective Chief Inspector Kate Blackburn, of Specialist Crime South, who is leading the investigation, said: "Our thoughts are with Yeray’s family at this unimaginably difficult time. They are being supported by specialist officers.
"The incident took place in the middle of the road outside the McDonald’s on Old Kent Road and there were many witnesses.
"Were you in the area at the time of the stabbing? Were you driving and have dashcam footage of the Old Kent Road? Did you witness the incident?

Head of Investigations