The purpose of this article is to explore the ways in which the European Union (EU)’s counter-terrorism discourse, the ‘fight against terrorism’, is constructed, and the ways in which it functions both rhetorically and in practice. It argues that ‘EU identity’ is constituted through and is central to the constitution of EU counter-terrorism policy. The approach taken is constructivist in nature, drawing on a discourse analysis of primarily European Council policy documents, as well as the reports and speeches of the EU Counter-Terrorism Co-ordinator. In particular, it identifies three strands of the discourse that, it is argued, play a key role in the construction of a terrorist ‘other’. These three strands include terrorism as crime and as an emotive act of violence; terrorism as an act perpetrated solely by non-state actors; and terrorism as a ‘new’ and ‘evolving’ threat. The article proceeds in three steps. First, it outlines the theoretical considerations that underpin this research, including its empirical application. Second, it demonstrates how each strand of the discourse is constructed. Third, it discusses the functioning of the discourse, including the contested nature of the ‘terrorism knowledge’ that underpins the EU’s counter-terrorism approach. The article concludes by reflecting on what this case study contributes to our understanding of EU counter-terrorism policy, as well as explaining how the notion of the terrorist ‘other’ could provide the basis for a future research agenda that deepens our understanding of how the identity of the EU is constituted.