The incident took place near Sikandara village as the MUV carrying a dozen family members to their home in neighbouring Jharkhand from pilgrimage in Rajgir collided with a truck.
Three women, identified as Kusum Devi, Chinta Devi and Hemanti Devi, died on the spot, while nine others sustained injuries, Rajgir's Sub-Divisional Police Officer (SDPO) M K Rajak said.
The bodies have been sent for post-mortem while the injured persons were admitted to a government hospital at Giriyak.
The attending doctors referred five of them to Sadar Hospital at Biharsharif in view of their serious condition, he said.