Between the mid-1980s and 2002, the proportion of young people entering higher education at the age of 18 rose from 11 per cent to 27 per cent but David Raffe, director of research in the school of education, said this had mostly benefited the middle classes.
Attainment and participation in higher education were substantially up and proportionately more young Scots gained qualifications and went on to university than in England and Wales.
Professor Raffe said: "Despite wider inequalities, Scottish working-class youngsters consistently outperformed their English peers. But inequalities within each Scottish cohort grew wider between the ages of 16 and 18."
The Scottish upper secondary system encouraged participation in university education "but the most advantaged social classes responded most".