Azim Azam was on a bus travelling into Birmingham for his first day of higher education when he got into a disagreement with another teenager.
The Mirror reports the row continued as the teens got off the bus, and that Azim was stabbed in the chest.
The boy then collapsed in a pool of blood after attempting to stagger down the street.
Paramedics raced to the scene, but Azim died soon after arriving at hospital.
A witness told the paper he had seen Azim 'stumbling up the road' attempting to shout. Another bystander claimed Azim said he had been stabbed and lifted his clothes to show the wound.
Detective Chief Inspector Simon Wallis from West Midlands police is leading the investigation into Azim's death. He said the youngster had 'needlessly lost his life'.
"Our thoughts are with the family and friends of the deceased and specially trained family liaison officers are supporting them during this very difficult time," he said.
"We're working hard to understand the precise circumstances surrounding the attack. At this time it is unclear if the attack happened on the bus or in the street. Because of this I need anyone who was on the number 2 bus this morning around Yardley Wood Road to contact me immediately.
"We are committed to finding the person or people responsible and bringing them before the courts."
Azim had been on his way to Bournville College in the city. They issued a statement confirming 'a young man due to commence college has sadly been involved in a fatal incident'.
Azim's family have been informed, and a post mortem is due to take place this week. A Facebook page has been set up in his memory. One comment said: 'Knife crime is PATHETIC.'