Around 50 people were reportedly on board when the bus was supposed to drive onto a ferry but instead ended up in the water.
Many of the passengers were able to swim to safety, but others were trapped in the water-filled vehicle. Among the dead are at least five children.
The bus was heading towards the capital, Dhaka, from the southwestern parts of the country. Many Bangladeshis are currently returning home after celebrating Eid al-Fitr.
