From trolls and bot farms to “deep fakes”, fake news seems to dominate our every discussion about the future of media and the internet. So what can we do about it? Detection algorithms remain quite unreliable, fact-checks are important but also slow, and attempts to legislate our way out of the problem quickly run into issues with freedom of the press and expression. At the individual level, however, social psychology and behavioural science can offer a way out. In this talk, I explore the concept of a psychological “vaccine” against fake news: an online game in which players learn about how fake news is created and spread by taking on the role of a fake news creator. By learning about fake news techniques from the inside, my work shows, people become much better at spotting deceptive content online, and less likely to share it with their contacts.