The accident happened on the Aughnacloy Road in Banbridge.
Inspector Gregory Beckett said: “The boy tragically died at the scene of the two vehicle collision which occurred at around 5.20pm on Saturday evening, involving a silver Audi Q3 and a silver Ford Focus.
“Three other people have been taken to hospital and are being treated for injuries which are described as serious.
“The road was closed for some time following the collision but has since re-opened.
“We are appealing for anyone who witnessed the collision or who may have dashcam footage to contact local officers in Lurgan or the Collision Investigation Unit on 101 quoting reference 994 21/07/18.”
A man, a woman and a child remain in hospital this morning following the crash.