It happened on the Loughill Road in the village of Cloughmills, near Ballymena at about 8.30 am on Tuesday.
Three children were taken to Antrim Area Hospital. One of them is described as “very serious”.
Tragically, Adam Gilmour died of his injuries
The woman was taken to the Causeway Hospital in Coleraine in a serious condition.
Four ambulances attended the crash. A police helicopter has been flying overhead and forensics experts remain at the scene.
The road has now reopened at its junctions with Main Street and Lislaban Road.