Transport Minister Humza Yousaf said the SNP Government will hold a consultation on changes to the national concession travel scheme.
He wants to extend it to Modern Apprentices and those on Job Grants and said people who already had passes would retain them.
The Scotland-wide free bus pass entitlement scheme allows passengers, aged over 60 or disabled, to travel free on local, registered or scheduled long-distance services.
The Transport Minister has said a public consultation on changes to the current system will be held. Current holders of the passes would be unaffected.
Mr Yousaf told BBC Scotland:
"If you have a free bus pass you will continue to have that free bus pass and continue to be able to use that pass in the way that you currently are. What we have said is that we want to extend the national travel scheme to Modern Apprentices, to those on a Job Grant, so that some young people who are most need can also benefit.
"Clearly people are living longer and working longer - which are all good things - but it does add a financial pressure. So we will consult on the long-term sustainability of the national concession travel scheme and we look forward to hearing people's views."
Asked if the consultation was likely to result in a rise in the age at which people will qualify for free travel, the Transport Minister said:
"I don't want to pre-empt any consultation. Our budgets are continually being cut by the UK Tory Government and we have to make sure our budgets go further. So if you have a pass you will absolutely continue to have that pass. I would urge everyone to get involved in the consultation."