The UK has come 20th in the biggest ever ranking of the world's best school systems, trailing behind less developed countries such as Vietnam.
It also showed around a fifth of school leavers are failing to reach a basic level of education in the UK, and that improving this could add trillions of dollars to the UK economy.
Paris-based think tank the OECD's Universal Basic Skills report crunches test scores in maths and science across 76 countries. It comprises more than a third of the world's nations, including countries such as Iran and Peru.
Asian countries dominated the list with city state Singapore clinching the top spot, followed by Hong Kong, South Korea and then Japan and Taiwan in joint fourth place.
African countries Morocco, South Africa and Ghana were among the lowest ranking countries.
So what are Asian countries doing that we're not?
"These countries are also very good at attracting the most talented teachers in the most challenging classrooms, so that every student has access to excellent teachers," said the OECD's education director, Andreas Schleicher.