In this study, we set out to explain extreme left-wing and extreme right-wing ideologies within and between 30 European countries in a multi-level framework. To test our hypotheses, we use data from the European Social Surveys of 2002, 2004, 2006, 2008 and 2010 (N = 176.803), enriched with country characteristics. Our results show that lower educated people and manual workers are more likely to support left-wing extremism, because they are of the opinion that the government should take measures to reduce differences in income levels. Interestingly, the lower educated and manual workers are also more likely to have an extreme right-wing ideology. This effect, however, is explained by a higher level of perceived ethnic threat. At the country-level, our analyses indicate that a heritage of a totalitarian regime increases the likelihood for an individual to hold an extreme left-wing and extreme right-wing ideology. Moreover, we found a positive effect of the percentage of unemployed people in a country on the probability to support left-wing extremism.