The 19-year-old man, who died following a two vehicle road crash in Banbridge, Co Down, has been named as Niall Rodgers.
He was from the Newcastle area.
The collision happened on the Castlewellan Road, Ballyward at around 3.30pm on Sunday.
Four other people - three males and a female - were taken to hospital for treatment. "Their injuries are not believed to be life threatening," a PSNI statement said.
Police have appealed for anyone who may have witnessed the crash, between a Vauxhall Corsa and Renault Scenic, to come forward.
The Castlewellan Road has reopened after it was closed for a period on Sunday.
Meanwhile, another crash took place on Sunday in Omagh, Co Tyrone.
It happened on the main Omagh to Newtownstewart Road shortly after 1pm. The extent of any injuries is not known.