The crash happened in the early hours on the Stornoway to Tarbert route on Lewis.
The driver, who was the single occupant of one of the vehicles, was killed.
It is understood there were six people travelling in the other car, several of whom have been taken to the Western Isles Hospital for treatment.
Emergency services were called to the collision on the A859 at around 6.35am.
Two fire crews attended the scene along with police and ambulance teams.
Northern Constabulary closed the road for several hours as investigators attended the crash site.
Police advised motorists to find an alternative route but warned of ice affecting the surrounding roads.