The present paper represents an exploratory, dynamic and qualitative application of Social Network Analysis (SNA) for modelling the development of Islamist terror cells in the West. Two well-known case studies are systematically re-examined using this methodology as a supporting framework for interpreting the sequence of group development from a social psychological perspective. By drawing attention to salient features of evolving network structures, insight is gained into group functioning and underlying social-psychological mechanisms of radicalisation. This article represents a starting point for giving greater methodological and theoretical recognition to the dynamic structural properties of Islamist terrorist groups in the West. It is intended to stimulate discussion and ideas for future, more rigorous research.