The latest results from the Programme for International Student Assessment (Pisa) show that East Asian countries still dominate the top of the tables, particularly in science and maths.
Singapore has come top in science, maths and reading. And East Asian countries have taken the top five places in maths and three of the top five places in science.
But in reading, while the top two places are taken by Singapore and Hong Kong, the next highest performers are Canada, Finland and Ireland. And in science, Estonia and Finland have made it to the top five.
Pisa: focus on science
Pisa 2015 shows how 15-year-olds perform in each subject. The tests were taken by 540,000 pupils in 72 countries. The tests in science, maths and reading are taken every three years, but each round has a different focus - in this round, the focus was science.
The UK moved up six places in science to 15th place from 21st place in 2012, despite a drop in scores.
In maths, the UK dropped one place from 26th to 27th and in reading, it rose from 23rd place to 22nd.
Pisa is run by the Organisation for Economic Co-operation and Development (OECD).
The top 30 countries in each subject are shown in the tables below:
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