The bus was connected to the Dervock Young Defenders flute band.
Police said the fire, outside an Orange hall on the Carncullagh Road, was reported to them at about 05:30 BST on Friday.  It is being treated as a hate crime.
It is understood the flute band's instruments and other equipment were on the vehicle.
"The cause of the fire is being investigated and we are appealing for witnesses to come forward," Insp Michael McDonnell said.
DUP assembly member Mervyn Storey said he had spoken to police about the incident.
"If this was arson I would appeal for full cooperation with the police and that there is no retaliation," he said.
"Regrettably there are a small element of individuals who are determined to spread sectarian hatred."
Earlier, Ulster Unionist councillor Darryl Wilson said he believed it was an arson attack and that "thousands of pounds worth of instruments and pieces of equipment" had been destroyed as a result.
"The bus was used by the wider community, it was used by the youth development programme in the village, it was used by a number of other organisations within the village," he added.
"The community relied on this bus, it was the community who fought hard for the bus and gathered up funds for the bus over a number of years so it will be a devastating loss to not only the band but the entire community.
"This was not only an attack on the band, but an attack on the entire village as the bus was utilised by the community on many occasions throughout the year."
Ray Laverty of the flute band expressed his sadness at what had happened and believed a number of drums he used had been destroyed.
"To me, I have lost a huge chunk of my heart," he added.
The Orange Order has condemned the attack and said those responsible had "nothing to offer society - only turmoil and discord".
A bus used by a loyalist band has been destroyed in a fire in Dervock, County Antrim.