Police were called to the crash involving a car, a 395 bus and pedestrians on the A312 Bessborough Road at 9.19pm yesterday (February 24).
The air ambulance attended alongside officers and paramedics but a woman in her 40s, a pedestrian, died at the scene.
Two other pedestrians were taken to hospital in a non-critical condition.
The driver stopped at the scene and was arrested on suspicion of causing death by dangerous driving.
He remains in custody.
Road closures were put in place but have since been lifted.
A Metropolitan Police spokesperson said: “Detectives are appealing for witnesses and any road users with footage following a fatal collision in Harrow.
“Police were called at 21:19hrs on Monday 24 February to reports of a collision on Bessborough Road, Harrow involving a car, a bus and pedestrians.
“Offices, London Ambulance Service and London’s Air Ambulance all attended.
“Despite the best efforts of emergency services one of the pedestrians, a woman aged in her 40s, sadly died at the scene.
“The two other pedestrians were taken to hospital for treatment – their conditions are not life threatening.
“The driver of the car stopped at scene and he was arrested on suspicion of causing death by dangerous driving. He remains in custody.
“Road closures were put in place while the scene was dealt with but have since been lifted.
“Officers are appealing for witnesses or anyone with footage of this incident, including drivers with dashcam footage, to contact police on 101 or ‘X’ @MetCC quoting CAD 7193/24FEB25.
“You can also provide information anonymously to the independent charity Crimestoppers on 0800 555 111.”
