She was a passenger in an Audi A3 which was travelling along Whinby Road between the Higham roundabout and Barnsley Business Park when it crossed to the opposite side of the road before colliding with a Mercedes Sprinter van and a VW Transporter van travelling in the opposite direction.
The girl suffered a serious head injury. A four-year-old boy, also a passenger in the Audi, and the driver, a 31-year-old woman, both suffered minor injuries.
A 47-year-old man in the VW Transporter van was treated for minor injuries at the scene.
Anyone with information should call 101 quoting incident number 498 of September 14.