Independent school Brighton College was among the highest performing in the country for GCSEs.
The Eastern Road school was also one of only five in England with an average A-Level score higher than a grade A.
At GCSE, the new Attainment 8 measure put Brighton College well ahead of other independent schools in England, with a score of 80.2.
Headmaster Richard Cairns said: “We put so much focus on ensuring that pupils are happy in their own skins and there is an obvious link between cheerful, positive youngsters and high achievement. We also have a cadre of truly outstanding inspirational teachers. We never lose sight of the fact that a school is only ever as good as its teachers.”
“It is fascinating to note too that, as in the state sector, schools in London and the South East are pulling ahead of the rest of the country. It must be a source of concern to note that there are no schools in the Midlands, South West, or North in England’s top 10.”