The UK health service was praised for its safety, affordability and efficiency.
The research by the Commonwealth Fund, a US think tank, looked at countries across the world, including the USA, Canada, Australia, France and Germany and the USA came bottom.
It is the second time in a row that the UK has finished top. Three years ago, when the survey was last done, the UK was also number one.
It comes despite the NHS being in the grip of the tightest financial squeeze in its history with lengthening waiting times.
4 = New Zealand
4 = Norway
6 = Sweden
6 = Switzerland