Post-9/11, the concept of radicalization has come to prominence as a means of explaining the process by which individuals become attracted to extremist ideology and go on to endorse or enact terrorism. Over the last decade, discourses of radicalization have steadily gained traction in policy, political and media circles, leading to the common assumption that there are particular phases through which people travel before they commit to enacting violence on others. In order to interrogate the assumptions that underpin contemporary understandings of radicalization, we will draw on the cases of young men apparently inspired by radical Islamism who were involved in terrorist attacks in France in 2015 and 2016. To this end, we utilize biographical vignettes to problematize the assumptions made in the discourse of radicalization, noting key elisions. In particular, we question the concentration on religious ideology as a primary facet of radicalization drawing on both case material and conceptual critiques. At a theoretical level, we consider the implications of the framing of radicalization for criminology and identify ways of thinking more deeply about the political and religiously motivated violence.