The narrative around contemporary terrorism and political violence has emphasise its transnational character. There has been a tendency to see this dimension of terrorism as something novel, rendering contemporary terrorist threats as more dangerous than those experienced in the past. The idea of globally networked violent actors is frightening, and understandably excites public anxiety. Yet the overwhelming majority of terrorism has tended to be not only domestic, but local, conducted by individuals in the country where they normally reside, usually striking at targets close to their home. Transnational connections do exist, of course, but rather than being the defining feature of some ‘new’ terrorism, they have been a feature of violent political movements since long before 11 September 2001. Indeed, they arguably date back to the emergence of terrorism itself as some phenomenon discernable from other forms of violent contestation. This chapter has two aims. It will assess the importance of transnational links to radical and violent non-state actors for Irish Republicanism. Further, through an analysis of the Irish case study, it aims to contribute to our understanding of such transnational links more generally.