The group were riding pedal cycles when they were struck by a van which was overtaking a car.
Driver arrested after biker hit by stolen Volvo in ArmleyWest Yorkshire Police said:
"At about 7.10pm on Monday, the victim, 14, and two other boys, both aged 15, were riding their bikes along Bullerthorpe Lane southbound in the direction of Woodlesford.
"All three boys were involved in a collision with a white Mercedes Sprinter dropside van that was heading in the opposite direction towards Colton.
"The van is believed to have been overtaking a white Volkswagen Polo at the time of the collision, which it also collided with. Both vehicles and drivers remained at the scene.
"The 14-year-old boy was taken to Leeds General Infirmary by air ambulance for emergency treatment but later died as a result of his injuries.
"The two other boys were also taken to hospital by ambulance.
"One 15-year-old boy received serious injuries and remains in hospital in a stable condition. His injuries are not considered life threatening.
"The other 15-year-old received only minor injuries and was released after medical assessment.
"The driver of the van, a 28-year-old man from Castleford, was arrested on suspicion of causing death by dangerous driving and is currently in custody."
Sergeant Carl Quinn, of West Yorkshire Police Major Collision Enquiry Team, said:
“This is clearly a very tragic situation for the family of the boy who has died and we are doing everything we can to support them at what is understandably a very difficult time for them.
“We are carrying out extensive enquiries to establish the full circumstances of this incident and we would like to hear from anyone who witnessed the collision itself or who saw the vehicles involved or the three boys on bikes in the time leading up to the collision.
“We are particularly keen to hear from anyone who has any dashcam footage that could assist the investigation.”
Anyone with information is asked to contact the Major Collision Enquiry Team via 101 quoting reference 13180530099.