Current literature finds that radicalization is correlated with both the holding of fundamentalist religious beliefs and low socio-economic status. The authors interrogate these proposed relationships through a survey we commissioned of 1,200 Muslims living in Western Europe. They analyze, inter alia, Islamic religious fundamentalism, and explore its relationship to self-reported affluence. Controlling for demographic variables, they find that, on average, respondents from more prosperous families are more likely to practice Islam in a way closely associated with fundamentalism – they are more conservative regarding gender roles, seek the universal application of Islamic law, and embrace attitudes associated with a more politicized Islam. This relationship is strengthened among respondents who are unattached to the labor market due to unemployment. Additionally, respondents espousing this belief set are more supportive of the use of violence to ‘defend their faith’.