The incident occured near Machecha village when the family was on its way to Shahjahanpur, they said.
Rakesh Tewari (40), his wife Seema (37), six-month-old son Prabhu, his uncle and aunt were killed and his daughters Pragya (12), Preksha (8) and niece Priya injured when the car was hit by the jeep, they said.
While Rakesh and his aunt died on the spot, Seema, Prabhu and his uncle succumbed to his injuries on way to hospital, they said.
A case has been registered in the matter, police said.