Oxford University's intake of new students this autumn will have the highest proportion of state school pupils for at least 40 years.
The university has offered 59.2% of places to pupils from state schools, up from 55.6% of places taken last year.
Top universities have faced calls to be open to youngsters from all backgrounds and to support social mobility.
Dr Samina Khan, head of undergraduate admissions at Oxford, said they took diversity "incredibly seriously".
The Independent Schools Councils estimates the independent sector educates around 6.5% of school children in the UK - with about 93% of all pupils educated in state schools.
The final figures for acceptances remain unconfirmed, but university officials expect the highest intake from the state sector for decades.
The university says directly comparable admissions figures go back to 1990 - and the 2016 level of state school entries will be higher than any year since then.
State students at Oxford timeline
- 2016: 59.2% of offers to state schools
- 2010: 55.4% of students from state schools
- 2005: 51.4% of students from state schools
- 2000: 51.9% of students from state schools
- 1995: 48.1% of students from state schools
Admissions statistics for the 1980s were gathered differently but were below this latest increase for state school students.
House of Commons library figures for the 1970s show state school admissions at Oxford consistently below 50% - and in 1961 there were 34% of Oxford entrants from state schools.
Prime Minister Theresa May and her predecessor David Cameron - both Oxford-educated - have called for greater efforts for universities to promote social mobility.
Mr Cameron earlier this year attacked top universities for doing too little to attract talented youngsters from poorer backgrounds and from ethnic minorities.
Oxford, rejecting criticism that it is socially exclusive as well as academically selective, has invested heavily in outreach projects, spending more than £6m per year.
These have been designed to encourage applications from a wider range of backgrounds and to challenge pre-conceptions about elitism.
Last year, the university and its colleges took part in 3,000 outreach activities involving 3,400 schools, which it says is a 40% increase on 2011.
Dr Khan, in charge of undergraduate admissions, says the increase in state school entries shows its effort to attract applications from under-represented groups were now "bearing fruit".
Among the projects encouraging applications from state schools is the Liverpool to Oxbridge Collaborative.
"I'm very aware that the best known private schools do a lot of work to prepare their most academic students to apply for Oxford and Cambridge," said former education minister, Stephen Twigg.
"So the reason we set up the Liverpool to Oxbridge Collaborative is to give young people in secondary schools in my constituency in Liverpool the same chance.
"There are some pre-conceptions about what the place is like," says Mr Twigg.
"A lot of young people still think, particularly if they come from a working class background and a state school, that they will feel out of place."
The project arranges visits by sixth formers to Oxford and Cambridge to try to demystify the application process.
Mr Twigg accompanied a group from Liverpool visiting St Peter's College and he described his own "trepidation" when he left his comprehensive school to become a student at Oxford more than 30 years ago.
"I was extremely nervous. I spent the summer of 1985 wondering if I'd made a mistake, because no-one else from my school was going."
St Peter's College has its own school liaison officer, Lucy Dixon, who says she is keen to break down any "misconceptions" that pupils might have about applying.
"We're very keen to make sure that no matter where you're from or whatever your background you have all the information you need.
"Students think they have to have all A*s at GCSE. They don't realise that we use a lot of contextual data in our admissions, to see how they've done compared with their school's average."
But in terms of public perception, Oxford and Cambridge have struggled to disentangle the idea of academic excellence from social elitism.
Debates about Oxbridge admissions are often really about class, rather than who is top of the class.
Ms Dixon's own story shows the intimidating cultural divide that can exist for some young applicants.
She went on to study at Cambridge, but describes going to a Cambridge open day on her own, where she had "left by the morning because I got scared".
"I went to one college, I thought 'What am I doing here?' I felt a bit nervous. I got back on a train to west Wales. Six hours there, six hours back."
Students taking part in the St Peter's College trip described their preconceptions.
Most of their parents had not gone to university - and there had been apprehensions about Oxford's image.
"The architecture makes you think it's a high class kind of place," said one of the teenagers.
They said meeting students and staff at Oxford had helped to make the university seem more accessible and they had not found it "snobby".
The Liverpool students seemed confident of a level-playing field.
"It's not about what school you went to, it's about how much you want to do something."
And while Oxford's image might once have been associated with Brideshead Revisited, these teenagers described it as looking like the more approachable Hogwarts.