Increasing tuition fees to £7,000 per year would mean a sharp drop in young people wanting to go to university, says a survey.
The Sutton Trust education charity has published research showing 80% of 2,700 youngsters asked in England and Wales expect to apply to university.
But it warns a steep rise in fees could mean two-thirds changing their minds.
Trust chairman Sir Peter Lampl says many young people who miss out on places would be "sorely disappointed".
The research from the Sutton Trust comes against the background of Lord Browne's review of university funding in England.
This could allow universities to charge tuition fees higher than the current maximum of £3,225 per year.
The Sutton Trust's study of 2,700 young people aged 11 to 16, carried out by Ipsos Mori, says that an unprecedented four out of five young people now expect to go to university.
Universities have warned that they are facing a huge demand for places this summer - up 16% year-on-year - with applications climbing sharply in recent years.
There could be as many as 250,000 more applications than there are places this summer.
The survey from the Sutton Trust suggests the demand for places is going to intensify even more.
But it includes a strong warning that such ambitions could be punctured by much higher tuition fees.
It identifies the crunch point for fees as being £7,000.
If fees rise to £5,000 per year, the survey suggests a limited deterrent.
But if fees were to be lifted to £7,000 per year, only 45% would want to apply.
And if fees reached £10,000, the number of young people wanting to apply falls to 26%.
The survey also found a low level of awareness among teenagers of the financial support that might be available for students.
Trust chairman Sir Peter Lampl said it was important that young people from poorer backgrounds should not miss out because of a pressure on university places and increased fees.
"The findings are also a warning that significantly higher fees may affect university participation.
"If Lord Browne's review concludes that higher fees are necessary, there is a significant task ahead in ensuring that all young people - and particularly those from non-privileged homes - are equipped with the information they need to make well-informed decisions," said Sir Peter.
A Department for Business Innovation and Skills spokesman said: "The coalition programme makes it clear that the criteria for any reform include increasing social mobility and attracting a higher proportion of students from disadvantaged backgrounds."