Humza Hussain died following the stabbing on Stoneygate Road, near Challney High School for Boys on Tuesday.
Police said on Sunday a 16-year-old boy has been charged with murder and possession of a bladed article following the incident, which took place on a Tuesday afternoon.
The boy remained in custody ahead of a court appearance this week, Bedfordshire Police added.
A second teenager was arrested on suspicion of violent disorder and has been released on bail, according to police.
Challney High School for Boys said last week they understood no current students were involved in the incident.
A post mortem on 10 June found Humza, from Luton, died from stab wounds.
His family paid tribute to the “much-loved son, grandson and brother” following his death.
“We are extremely saddened and heartbroken at the passing of Humza. He was a young boy with his whole life ahead of him, and this should never have happened,” they said in a statement.
They said it was a “very sad loss” for the family and asked for their privacy to be respected.
Police have asked anyone with information about the incident, particularly anyone with dash cam or other camera footage from Stoneygate Road between 3pm and 4pm on Tuesday 8 June, to contact them on 101 or through their online reporting service. They should quote Operation Alstroemeria.
People can also share information by speaking anonymously to Crimestoppers on 0800 555 111.