Research on radicalisation and social movement studies are related and, to some extent, overlapped fields. This chapter takes a closer look at the relationship and interaction between these sub-disciplines, examining, in particular, how social movement theory, with its emphasis on networks, socialisation, framing, or spaces/milieus, has impacted radicalisation research, contributing to an analytical shift towards context, relations, and processual approaches more generally. It explores the extent to which recent work on the role of emotions as well as performative and experiential aspects of protest and micro-mobilisation might provide further, so far underexploited, analytical resources for the study of radicalisation. But it also draws attention to the fact that, notwithstanding the productive exchange between these fields and theories, underlying differences have not disappeared, and the epistemological implications of social movement theory are not always fully recognised.