Bus Éireann is to carry out an investigation to determine what caused the fire on the Route 64 Sligo to Galway bus service this evening at Charlestown.
The vehicle will be examined in detail in the coming days in an effort to ascertain whether an electrical fault was the cause of the blaze
More than 40 passengers were evacuated after a fire broke out on board.
It is reported that smoke was seen coming from the dashboard shortly before the bus arrived in the east Mayo town.
After the passengers disembarked, the area around the driver's seat caught fire.
According to RTÉ News, the heat from the flames caused a window on the bus to shatter but the blaze was brought under control soon afterwards by fire service personnel.
No injuries were sustained during the incident.