A passenger boat sank in the Teesta River in Burirhat area under Rajarhat upazila on Sunday noon.
Upazila Nirbahi Officer Md Rashedul Haque said the boat from Burirhat was going to Sitabkhan.
There were strong currents in the river when the boat sank around 11am, the UNO said.
It is unclear how many people were on board but Gharialdanga Union Parishad Chairman Rabindranath Karmokar said a boat usually ferries 35 to 40 passengers at a time.
It was not immediately clear if anyone has died.
Divers of Fire Service are looking for the missing passengers.
Thousands of people, including relatives of many of those missing, have gathered in the river bank.