Children should be taught how to recognise "fake news", the Organisation for Economic Co-operation and Development's education director has said.
Fake news, in which falsehoods are presented as being factual, are often placed on websites which look like official media outlets.
Schools need to teach pupils to think critically and analyse what they read on social media and news sites, said Andreas Schleicher.
The education director plans to include questions about "global competencies" in future international Pisa tests.
He believes schools should ensure children have a chance to debate different views and opinions outside of the "echo-chamber" where they may only hear views similar to their own.
Mr Schleicher said information could be more easily trusted in the past: "When you needed information, you went to an encyclopaedia, you looked it up, and you could trust that information to be true."
It comes as the inventor of the World Wide Web says he is concerned about impact of fake news and is calling for greater protection laws.
Sir Tim Berners-Lee said that the misuse of data has created a "chilling effect" on free speech, and warned of democracy-corrupting "internet blind spots".
In February Apple boss Tim Cook said fake news is "killing people's minds", and that the phenomenon needed to be tackled.
Notorious fake news headlines have included "Pope Francis shocks world, endorses Donald Trump for president" and "Isis leader calls for American Muslim voters to support Hillary Clinton".
Mr Schleicher said that anyone using social media or even news sites has to be able to assess, evaluate and reflect on the information they are given.
"Exposing fake news, even being aware that there is something like fake news, that there is something that is written that is not necessarily true, that you have to question, think critically. That is very important", he added.
Mr Schleicher believes schools can pay a big role in ensuring children have the skills needed to avoid believing fake news.
"Schools can do a lot to equip students with the kind of cognitive ability to access and analyse meaning, culture, practice, things like this," he said.
He added that it is not a matter of schools teaching a new subject, but building these skills into all lessons, from science to history.
Mr Schleicher also suggested that social media can reinforce one single viewpoint.
"Social media is designed to create an echo chamber. We are likely to talk with people who are like us. Who think similarly to us.
"And that's precisely, almost the antithesis, to global competency."
New computer-based "global competencies" tests will be taken by 15-year-olds around the world alongside the OECD's current reading, maths and science assessments which are conducted every three years.
The tests are due to be taken next year, with the results published in 2019.