The teenager was a front-seat passenger in a car that crashed into a ditch near Scartaglen, Co Kerry, at about 11.25pm on Sunday.
Gardai said an 18-month-old baby who was also in the car was treated in hospital for non life-threatening injuries, along with the driver, a 20-year-old woman. No-one else was injured.
The road was closed for several hours to allow for forensic collision examinations at the scene and gardai at Castleisland have appealed for witnesses.
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