The deceased were identified as Akkas Ali, 40, his wife Hosneara, 35, their daughter Musfira, 8, and four-month-old son Hasan Ali, of Monnaffermor in the city, Asia, 30, wife of Ramjan of Godagari upazila and driver Mahanubur Rahman, 40, of Meherchandi in the city.
The accident took place on Rajshahi-Chapainawabganj highway around noon while they were going to attend a marriage ceremony, said Md Shahidullah, superintendent of Rajshahi Metropolitan Police (RMP).
Khairul Islam, officer-in-charge of Godagari Police Station, said three people, including the baby girl, were killed on the spot and four other suffered injuries.
On information, police recovered the bodies and sent the injured, including two children, to Rajshahi Medical College Hospital where they died, the OC added.