Latest figures from the Office for National Statistics show there were 792,000 young people (aged 16 to 24 years) in the UK who were not in education, employment or training (NEET) during the April to June period.
That was up 28,000 on the January to March quarter and 14,000 more than the same period a year previously
That meant the percentage of all young people in the UK classed as NEETs was 11.5%.
"Of all young people in the UK who were NEET, 41.6% were looking for, and available for, work and therefore classified as unemployed; the remainder were either not looking for work and/or not available for work and therefore classified as economically inactive," said the ONS.
The figures come on the same day that GCSE results have been announced.
They showed the pass rate edged up to 67.3% in England, Wales and Northern Ireland - 0.4 percentage points higher on last year.
The slight increase in the GCSE pass rate and the percentage of top grades this year came against a background of concerns about the difficulty of exams.