The family was travelling in a private bus and was on its way to Soorsagar area in Jodhpur from Parbatsar when the incident took place, they said.
The victims have been identified as Nainuram (55), his wife Nandu (50), their son Raju (35), his wife (30), and their sons Prithvi (13) and Bharat (11), police said.
The bodies have been sent for post-mortem, they said.
In another incident in Jhunjhunu district, a girl was injured when two buses had a minor collision due to fog in Nawalgarh, police said.