One in five children from Gypsy, Roma and Traveller families does not go to secondary school, according to new Government-funded research.
Around 20 per cent of 11-year-olds from nomadic communities leave education when they finish primary school.
And just 50 per cent of those who do go on to secondary school then stay there until the legal leaving age of 16. Many drop out in Years 8 and 10.
The researchers said teachers and other professionals need to "change hearts and minds" among the communities to encourage more children to stay on in education.
Their report said the "attitudes and behaviour" of both teachers and parents must improve. And those who run traveller education services say a lack of trust and fear of the school environment among their communities explains the staggeringly low attendance rates.
Only half of Gypsy, Roma and Traveller pupils who transferred to secondary school in 2003 were still in formal education five years later.
Roma pupils were the most likely to stay until the statutory leaving age - 63 per cent remain until Year 11. However, just 38 per cent of Travellers of Irish heritage were still in school at 16.
"The period of transition between Year 6 and Year 7 is the most vulnerable time... Around one in five Gypsy, Roma and Traveller pupils left the school system at this point," said the report, produced by the National Foundation for Educational Research for the Department for Education.
"The pattern of retention is still far from satisfactory for almost half of Gypsy, Roma and Traveller pupils. Furthermore, the data shows that pupils from all Gypsy, Roma and Traveller communities are still likely to withdraw from the school system ... during KS3 and, to a lesser extent, during Year 10."
Previous studies, which ran from 2000 to 2005, estimated that only around a third reach Year 11. Researchers say the improvement is due to "community attitudes beginning to shift" and "a greater recognition among parents and pupils of the need for a secondary and post-16 education".
"There may be opportunities for school staff and other professionals to build on this and contribute to changing 'hearts and minds' in relation to attitudes and behaviours surrounding non-transfer."
The study found pupils were most likely to stay on in schools which were "inclusive" and "reached out" to parents and families. Gypsy, Roma and Traveller pupils said other pupils were "unfriendly" to them. They complained that they had to "hide their true identity".
Teachers told researchers that pupils were "caught in the middle" between the aspirations of their family and those of the school.
The National Association of Teachers of Travellers is concerned that spending cuts will affect services run to help pupils from Gypsy, Roma and Traveller communities.
"There's still a lot of work to do to build up trust, and to develop schools so they are better able to meet the needs of these pupils," said vice-president Linda Lewins.
The report found Gypsy, Roma and Traveller pupils were "concentrated" in weaker primary and secondaries, often because they were the only schools with spaces. Around 41 per cent were in the lowest-achieving schools.
Cause for concern
The first Government warnings about the poor educational achievements of children from Gypsy communities came in 1971, when a report said they were receiving irregular or, in many cases, no schooling.
By the late 1970s, many councils were running specialist traveller education support services; they were given specific funding for this from 1990 onwards.
Despite this, Gypsy, Roma and Traveller children still continue to be the worst achieving ethnic group in schools. The first report on the issue was published by HMI (Ofsted's predecessors) in 1982. The most recent report concluded the situation was still "serious" and not enough had been done in the past 20 years.
All local authorities with three or more Gypsy, Roma and Traveller pupils in a single year group are required to set targets on their progress in KS2 and KS4. But there is no legal duty to run specialist support services.