The smash happened on the Hilltown Road in Kilcoo during the early hours of the morning, Saturday, October 26.
The 18 year old male was travelling in a blue coloured Volkswagen Bora that was involved in the collision shortly before 2.30 am.
Four other young people, two males and two females, who were also in the car were taken to hospital for treatment for their injuries.
One of the males is described as being in a critical condition.
Inspector Beckett is appealing to anyone who was traveling on the Hilltown Road early this morning and who may have seen this blue Volkswagen prior to the collision or anyone who has dash-cam footage which could assist with the investigation to contact police on 101, quoting reference number 167 26/10/19.
The Hilltown Road remains closed at this time while police continues to investigate the circumstances of the collision.