An evaluation of the Independent-State Schools Partnership Scheme, which has run since 1998, found that it had helped to break down barriers and led to greater understanding between pupils and teachers.
The study, Building Bridges, for the National College for School Leadership by James Turner, head of junior school at Sunderland high , found that once relations had been forged the differences between schools were not as great as had been imagined.
One state secondary head said: "You hear many stories of elitism and so on but we went into the school and saw children very similar to our own. They were hard working, and they had the same problems as our own.
"They had the whole range of academic ability and it was clear they could benefit from the expertise of my staff."
Many heads said their pupils benefited from mixing with children in other schools.
A secondary head said: "Our pupils were a little bit in awe at first because the pupils from our partner school speak with such assurance, but then they realised that their maths was every bit as good, sometimes better, than their students."
The head from the partner private school said it was a "positive eye opener" for his students to see the mix of pupils in a comprehensive. He said: "It was also very good for the students to see that many of the students there were better than themselves."
Another private-school head said that the scheme had benefited both sides equally. He said the project would dispel the notion that independent schools are "a Lady Bountiful" entering into partnerships with state schools. He said: "We do not see ourselves as being involved in teaching our state partner how to do things. This was entirely the opposite."
However, the study also found that partnerships only worked when there was commitment from heads and staff.