The blaze broke out on the vehicle on Castlemilk Drive in the city’s Castlemilk on Saturday evening.
According to Glasgow City Council’s Traffcom, the road was shut for around an hour.
Officers confirmed that they are treating the act as deliberate.
A Police Scotland spokesperson said: “Around 8.15pm on Saturday, January 20, 2024, officers received a report of a bus on fire on Castlemilk Drive, Glasgow.
“The road was closed and reopened a short time later.
“The fire is being treated as wilful and enquiries are ongoing.”
