The UK's school system is socially segregated, with immigrant children clustered in disadvantaged schools, research shows.
It says that the socio-economic make-up of the UK's schools poses "significant challenges" for immigrant students and those from disadvantaged backgrounds.
Some 80% of UK students with an immigrant background attend schools with a high concentration of immigrant students, according to the Organisation for Economic Co-operation and Development's (OECD) latest edition of Education at a Glance.
This is 12.4% higher than the OECD's average of 67.6%.
It also reveals that 79.8% of immigrant students with low-educated mothers (who do not have qualifications beyond GCSE level) are in disadvantaged schools.
This is a higher proportion than any other OECD country, and greater than the OECD's average of 55.9%.
More than half (57.1%) of non-immigrant children with low-educated mothers are in disadvantaged schools - only Canada, the Czech Republic, Hungary, Israel, Japan and the Slovak Republic have higher proportions.
"The socio-economic composition of UK schools poses significant challenges for disadvantaged students and students with an immigrant background," the study says.
The situation is not limited to children with low educated mothers.
Some 42.5% of immigrant students born to highly educated mothers - those who have a degree - are in disadvantaged schools.
This is also a higher proportion than any other country examined by the OECD, and almost double the OECD's average of 26.1%.
All of the figures relate to 2009.
Report author Andreas Schleicher said that social segregation, according to the OECD's indicators, is "one of the biggest contextual challenges for the UK".
Schleicher added: "What is really striking is that in the UK, highly educated mothers can end up in schools for their children where disadvantage is concentrated."
The OECD's report analysed and compared education at all levels in 34 OECD countries plus systems in Brazil, the Russian Federation, Argentina, China, India, Indonesia, Saudi Arabia and South Africa.
The report did find that the UK does better than many other countries in helping to improve people's life chances.
Over two in five (41%) of 25 to 34-year-olds in the UK have achieved a higher level of education than their parents, compared with an OECD average of 37%.
It adds that 25% of all 20 to 34-year-old university students have parents with low levels of education, above the OECD average of 17%.
The study also reveals that the UK saw the steepest increase in spending on higher education in 2009, with most of this money coming from private sources such as tuition fees.
And it found that students study for long hours. Pupils in England receive on average 7,258 hours of lesson time between the ages of seven and 14, compared with the OECD average of 6,862. Virtually all of this time is compulsory.