The ‘populist phenomenon’ has received a lot of attention in recent years. Yet little is known about the populists themselves: who are they? They are often described as bad-mannered provocateurs disrupting the political game, but also as charismatic leaders able to persuade and motivate. Can a populist ‘style’ or ‘personality’ be identified? This article assesses to what extent populists score differently from ‘mainstream’ politicians on established personality inventories. Using a new dataset based on expert ratings for 152 candidates (including 33 populists) having competed in 73 elections worldwide, it is found that populists score lower on agreeableness, emotional stability and conscientiousness. At the same time, populists score higher on extraversion, narcissism, psychopathy and Machiavellianism. These results have important implications for the study of the success of populists in contemporary democracies and beyond.