Emergency services raced to the scene after they were called out to a blaze on the A9 flyover near Auchterarder at around 9.30pm last night (Saturday, November 21.)
Five people were taken to hospital as a precautionary measure, but it is understood none of them were seriously injured in the incident.
A Police Scotland spokesperson said: "We received a report of a bus fire on the A9 flyover near Auchterarder around 9.30pm on Saturday, 20 November.
"Officers attended to help with road closures, alongside the fire service and ambulance service.
"There were not believed to be any serious injuries and five people were taken to hospital as a precaution."
This afternoon St Johnstone FC gave a short statement on Twitter about the incident and said it was pleased to report that no-one involved had suffered any serious injuries.
The club said its thoughts are with all those who were connected with the bus fire.
In a tweet it said: “Yesterday we were made aware that a supporters bus travelling home from the game caught fire. We are glad to report that everyone escaped without any serious injuries.
“We can't begin to imagine how scary that must have been, and our thoughts are with everyone involved.”