He died from injuries sustained in the crash which occurred when the Peugeot 306 car he had been driving was in collision with Volvo articulated lorry on the A37 Broad Road outside Limavady at around 2.15pm.
A passenger in the car, also in his 20s, was taken to the Altnagelvin Hospital where he is being treated for serious injuries which are not thought to be life-threatening.
A 45 year old man and a 34 year old man who were travelling in the lorry, were treated at the scene by paramedics.
Limavady Mayor Gerry Mullan said people in the area were “very, very distressed” by the accident.
He added: “This shocking accident really brings home the danger on the roads to you.”
It brings to 11 the number of people killed on the North’s this year.