Abstract: This article revisits and revives the concept of ‘the Stranger’ in theorising international relations by discussing how this figure appears and what role it plays in the politics of (collective) identity. It shows that this concept is central to poststructuralist logic discussing the political production of discourses of danger and to scholarship on ontological security but remains subdued in their analytical narratives. Making the concept of the Stranger explicit is important, we argue, because it directs attention to ambivalence as a source of anxiety and grasps the unsettling experiences that political strategies of conquest or conversion, including practices of securitisation, respond to. Against this backdrop, the article provides a nuanced reading of the Stanger as a form of otherness that captures ambiguity as a threat to modern conceptions of identity, and outlines three scenarios of how it may be encountered in interstate relations: the phenomenon of ‘rising powers’ from the perspective of the hegemon, the dissolution of enmity (overcoming an antagonistic relationship), and the dissolution of friendship (close allies drifting apart). Aware that recovering the concept is not simply an academic exercise but may feed into how the term is used in political discourse and how practitioners deal with ‘strange encounters’, we conclude by pointing to alternative readings of the Stranger/strangeness and the value of doing so.