In June 2016, British voters took part in a referendum on the UK’s membership of the EU. By a margin of 52%:48%, they voted to leave. Until now, polling data has consistently demonstrated that fixed demographic factors were the best predictors of voting intentions in either direction, but we investigated the role of moral intuitions. Before adding psychological variables, older age, being male, and lower educational attainment predicted the Brexit vote. After adding psychological variables, though, these were non-significant predictors of the vote. Instead, Brexit voting was predicted by political conservatism, ontological insecurities, and an adherence to the liberty foundation of morality. In contrast, only an adherence to the care foundation of morality was significantly predictive of a vote to remain in the EU. These findings were also reflected in linguistic analyses of campaign materials and news items. Our data question some common-sense commentaries of the EU referendum campaign.