Police sources said the incident took place late Friday night when the SUV fell into a canal after colliding with the tractor-trolley loaded with cane near Dariyabad village.
"Groom Devesh's brother-in-law Bipnesh and nephew Rudra (12) were killed on the spot and seven others were injured," they said.
Police sources said the injured, including groom Devesh, were taken to the district hospital where the driver succumbed to injuries.
"Devesh's marriage was scheduled to be held in Abhayan village in Kanth area of Shahjahanpur district.
"The groom and his family were going in different vehicles when one of the SUV met with an accident," they said.