The accident occurred at around 5.30 am when the victims were returning home from Mahalaxmi temple in Dahanu taluka, Vikramgadh police station inspector Sunil Nandwalkar said.
The deceased were identified as Jayprakash Yadav (30), his wife Neelam Yadav (27) and autorickshaw driver Kailas More.
The three injured included Jayprakash's one-year-old son. They have been shifted to a hospital in Mumbai as their condition is stated to be serious.
The bodies were sent to a local hospital in Vikramgadh for postmortem.