"They were travelling on a cement-laden truck...11 of them died instantly and five succumbed to their wounds on the way to or at two hospitals," a police officer told PTI.
Four among those dead were women while one was a 10-year- old girl.
Highway Police camp in-charge Hafizur Rahman said that five people injured in the accident were being treated at a Rangpur hospital and had suffered critical wounds.
Media reports said the passengers were mostly poor garment factory workers or daily wage labourers, who had taken the cheap truck ride from suburban Gazipur to return to their families in northwestern Lalmonirhat district for the Eid festival.
Muslim-majority Bangladesh is preparing for Eid celebrations with tens of thousands of people expected to travel to their villages by buses, ferries and trains.
Shortage of vehicles prompted desperate travellers to undertake dangerous journeys on rooftop or stairs of trains, ferries and buses despite warnings. Many people also undertake cheap rides on trucks carrying goods.