The accident took place when the rickshaw the victims were travelling in collided with the bus, coming from opposite direction on Nadiad-Mahemdavad highway near Andhaj village, Kheda Deputy Superintendent of Police Makrand Chauhan said.
Ten passengers and the rickshaw driver died on the spot while two were immediately rushed to Ahmedabad Civil Hospital and another was admitted to Nadiad Civil Hospital in a serious condition.
The injured trio later succumbed to their injuries increasing the death toll to 14, Chauhan said.
The Gujarat State Road Transport Corporation (GSRTC) bus which hit the auto rickshaw was going to Ahmedabad from Pavagadh.