The teenager was a passenger in a Fiat Punto which crashed with a Mini Cooper near Cockermouth.
The 18-year-old driver of the Punto and the 23-year-old Mini driver are both in a serious condition in hospital, Cumbria Police said.
The road between Tallentire and Gilcrux was closed from 17:15 GMT until midnight.
A 17-year-old girl has died and two men were seriously injured after a Christmas Eve car crash in Cumbria.