This chapter functions as a literature review, beginning with a summary of some of the terminological issues surrounding the study of terrorism. This is followed by an overview of theorisations of terrorism as communication, that is, the theory that violent acts are communicative. We then discuss not the practices and (verbal) expressions related to clandestine violence undertaken by terrorist individuals or groups. We explore some of the findings from previous research relating to the patterns in terrorists’ words and communicative strategies. We then turn to violent jihadist discourse specifically considering issues around polarised language and its relation to grievance-based discourse, the creation of shared identity, intertextual use of historical and theoretical texts and evocation of authority. We conclude by suggesting why the dearth of research on terrorist discourse poses problems for the creation of viable counter-terrorism measures.