The incident occurred on the Sonepat-Meerut inter-state highway near Palri village, about 15 km from here yesterday, police said.
The injured persons were rushed to the local civil hospital from where nine were later referred to the PGIMS hospital at Rohtak for further treatment.
The bodies of the victims were sent for the postmortem examination.
Police said the accident occurred when a car driver coming from Uttar Pradesh side on its way to Sonepat tried to overtake another car near Palri village resulting in the collision. PTI COR SUN