Firefighters from Stourport and Kidderminster attended the blaze which happened on the A456 near the Blackstone Picnic Area at around 5.40pm yesterday.
The blaze, on the Diamond bus, led to police temporarily closing off Stourport Road for around half an hour while firefighters put out the flames and made the area safe.
Flames could be seen coming out of the back of the bus and the back window had smashed.
The driver was on board the bus at the time and he made the 999 call. No passengers were on the bus. The cause of the fire remains unclear.
Two hose reels and two breathing apparatuses were used by firefighters to clear the blaze.
Stourport Road was reopened by police at around 6.15pm.