The bus on its way from Thancchi to Bandarban plunged into the canyon after the driver lost control over the wheels while it was coming downwards from a slope.
"According to initial reports we received, 17 people were killed and many injured.... apparently it was caused by dense fog," chairman of the Thanchhi sub-district Khamlai Murong told PTI.
The paramilitary Border Guard Bangladesh (BGB) troops have launched the rescue campaign, official said.