Two fire engines from Morecambe and Lancaster were called out to Morecambe Road at around 8pm following reports of "black smoke" coming from the engine compartment of the bus, say fire crews.
Crews arrived to find the bus well alight.
A spokesman for the fire service said: "Two fire engines and crews, from Morecambe and Lancaster, responded to the report of black smoke coming from the engine compartment of a bus.
"Anyone on the bus had got off safely and firefighters used two hosereel jets to extinguish the fire then used a thermal imaging camera to ensure that there were no remaining smouldering pockets of fire."
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Nobody was injured during the incident.