The concept of ‘young radicals’ is gaining ground in a context of generalized discontent – often, this is due to the fact that young people engage increasingly in unconventional forms of political activism. Much less is known about young people holding radical political attitudes. This article advances our understanding of those young people who place themselves on the extremes of the ideological scale and investigates how those with radical right attitudes differ from those with radical left ones. Drawing on a survey that gathers data from nine European countries, with a sample of young people aged 18–35, we test those factors that have been used to explain why people use violent repertoires of action: social background, gender, political values, and prior experience in protest activism. The results relate ‘radicalness’ to experienced economic difficulties and the more contentious political activism. The difference between the young ‘radicals’ in right and left are, however, defined by gender and adherence to authoritarian values.