More than a third of Team GB's medallists were educated at private school, figures have shown.
Among those who claimed gold in their sport, more than one in four attended fee-paying schools. This is despite the private sector educating just 7% of the school population.
The figures come in the wake of concerns about sport in state schools and calls for an overhaul of school sports policy. In many state schools, sport is not a priority, which means independent schools with top-notch facilities are often the ones that produce elite athletes, the Sutton Trust suggests.
The trust's figures show that 37% of Team GB medallists went to private school in Britain. Around 27.5% of gold medal winners were privately educated, it concludes. In total, 43 Team GB athletes won at least one gold in 29 events.
Sutton Trust chairman Sir Peter Lampl said: "While we congratulate all our Olympic winners, this research shows that independent school students are more than five times over-represented amongst our medal winners relative to their proportion in the population - which is also the case at leading universities and in the professions more generally.
"This comes as no surprise as children in independent schools benefit from ample time set aside for sport, excellent sporting facilities and highly qualified coaches, while in many state schools sport is not a priority, and sadly playing fields have been sold off."
The study also shows that one in 10 British Olympic winners who attended a British university went to Oxford or Cambridge, and three fifths (60%) went to one of the nation's top selective universities.
At the last Olympics one third of Team GB went to independent schools, nearly 40% of British medal winners and 50% of gold medallists.
They included multiple gold medallists Sir Chris Hoy, a product of George Watson's College in Edinburgh and Ben Ainslie, who went to Truro School in Cornwall. Many of the equestrian team that competed this summer went to fee-paying schools.
But all of Team GB's boxing medallists (whose schools are known) went to state school, including gold medallists Anthony Joshua, Luke Campbell and Nicola Adams, said the Sutton Trust. Athletics gold winners Greg Rutherford, Jessica Ennis and Mo Farah were also educated in the state sector.