The mishap took place when the driver of the vehicle carrying a marriage party lost control on the steering wheel and it turned turtle, they said.
The accident took place at Phagumarh area of the district last evening, the police said, adding that they were rushed to the district hospital at Kishtwar.
One of the passengers Kajal Devi was declared brought dead by the doctors.
Three seriously injured were referred to Government Medical College hospital here for specialised treatment, they added.