Just after 12 p.m. PT Saturday, passengers noticed smoke in the cabin as the bus travelled along Highway 97C just outside of Merritt.
The driver pulled over and all 21 passengers got off safely, along with their belongings.
The bus, which was on its way from Vancouver to Kelowna, burst into flames a few minutes later.
No one was injured in the fire.
Passing motorists helped transport the passengers to the Kelowna bus station.
The cause of the fire has not been determined.