Police were called at 3.55pm on Monday, 14 March to reports of a stabbing on board a bus at High Road, Chadwell Heath.
Officers attended along with London Ambulance Service.
A 16-year-old boy was found with a stab injury and taken to hospital in a critical condition; he sadly died in the early hours of this morning.
His family have been informed.
An 18-year-old man was arrested nearby on suspicion of attempted murder and remains in custody.
A crime scene remains in place.
Chief Superintendent Paul Trevers of the East Area Command Unit Said: “Today a young man stabbed in Chadwell Heath has died of his injuries. The victim was only 16-years-old and I can only imagine his family’s anguish at this terrible time, my thoughts are with them, and with all those who have been affected.
“I know how deeply this will be felt in the local community and there will be extra officers patrolling to reassure you and answer your questions. Please do speak to the officers about your concerns, they are there to listen to you and do all they can to help.
“A person has been arrested on suspicion of murder and there will be a full investigation by homicide detectives.
“Violent crime is down across London, but that is no solace to those affected by it. As a police officer I know that we cannot tackle violent crime alone, it needs everyone to work together. Whether it is telling police about those who carry weapons or talking to young people about the dangers of knife crime, what we all do can make a difference. It is only with police, partners and our communities together, that we can stop this needless loss of life.”
Any witnesses or anyone with any information is asked to call the incident room on 0208 345 3715 or contact via Twitter @MetCC. Please quote CAD 4741/14MAR
To give information anonymously contact Crimestoppers on 0800 555 111 or online at crimestoppers-uk.org.