On the basis of empirical research on an underrepresented group—Turkish-Dutch youngsters—and an overrepresented group—converts—in Islamist extremist movements, we want to contribute to the debate on what fosters radicalization and resilience. While in both the underrepresented and the overrepresented group there are ample factors recognizable that are commonly identified as contributing to radicalization, Turkish-Dutch youngsters hardly become involved in Islamist extremism, while converts are involved to a larger extent than one might expect on the basis of the number of converts. To shed light on these findings, we will demonstrate how this differential involvement can be understood through the concept of “relational embeddedness”. We will demonstrate how the relational embeddedness of this underrepresented and overrepresented group contributes in various ways to either the lack of susceptibility or the susceptibility to involvement in Islamist extremist groups. We will do this with reference to their sources of identification, their religious socialization, and the availability of legitimate political pathways. In the concluding discussion, we will argue that these insights can contribute to a more nuanced policy approach.