Bus companies are not required by law to force parents with buggies to make way for wheelchair users in designated bays on vehicles, senior judges ruled.
First Bus appealed against a court ruling, won by a disabled man from West Yorkshire, that the firm's wheelchair policy was discriminatory.
Doug Paulley, 36, was denied access to a First bus to Leeds when a woman with a pushchair refused to move.
The Court of Appeal overturned a Leeds County Court judgement in his favour.
'Request not require'
Mr Paulley had attempted to board the bus in Wetherby to visit his parents in Leeds in February 2012.
But he was told to wait for another one when the woman with the pushchair refused to move because her baby was asleep.
First's policy was one of "requesting but not requiring" non-disabled travellers, including those with babies and pushchairs, to vacate space needed by a wheelchair user.
In September, a county court judge said the firm's policy was in breach of the Equality Act 2010.
Mr Paulley was awarded £5,500 damages.
But earlier, judges at the Court of Appeal ruled the "proper remedy" for wheelchair users to get improvements in such cases was to ask parliament.
Lord Justice Lewison said: "The judge seems to me to have thought that the needs of wheelchair users trumped all other considerations.
"If that is what he meant, I respectfully disagree."
Clive Coleman, legal correspondent, BBC News
The net effect of this ruling is that if someone refuses to move from that designated, disabled, wheelchair-user bay on a bus or train then that is that.
The disabled wheelchair user will simply have to wait for the next bus or train.
Doug Paulley's lawyers have already sought a leave to appeal to the supreme court, the highest court in the land, for them to make a ruling on an issue which is of enormous importance to many, many disabled people in particular.
Lord Justice Underhill said: "It has to be accepted that our conclusion and reasoning in this case means that wheelchair users will occasionally be prevented by other passengers from using the wheelchair space on the bus.
"I do not, however, believe that the fact that some passengers will - albeit rarely - act selfishly and irresponsibly is a sufficient reason for imposing on bus companies a legal responsibility for a situation which is not of their making and which they are not in a position to prevent."
Lady Justice Arden she did not underestimate the difficulties of travel for wheelchair users "or their frustration at the pace of change".
Andy Cole, of Leonard Cheshire Disability said, the charity was disappointed with the judgement and it did not provide "clarity and certainty for disabled bus passengers that the space they need will definitely be made available".
Mr Cole said if the case moved to the Supreme Court he hoped any judgement would provide that certainty.