The 2008 Bluebird school bus was parked near the locker room after returning from a game in Three Rivers.
A short time later school employees noticed the fire and call for emergency personnel. No one was on the bus at the time of the fire.
According to school transportation officials, the bus started having engine problems near Kenedy.
The fire started in the motor and spread through the rest of the bus. Firefighters quickly brought the fire under control and the fire was extinguished.
According to Karnes City Fire Chief Charlie Malik, the exact cause of the fire is unknown at this time. School officials and mechanics are still investigating.