The vehicle went off the road while negotiating a sharp curve and rolled down, police said today.
The occupants of the car were on their way from Jispa to Gondla via Keylong when the mishap took place.
The bodies of the deceased were recovered with the help of locals and sent for postmortem.
The deceased included a retired DSP, Prem Chand Thakur, Chhering Angroop (65), Chhaten (70), Shivang (30) and Sonam Shering (13).
Lahaul and Spiti Deputy Commissioner Hans Raj Chauhan rushed to the spot and supervised the rescue operations.