Guest friendship — rendered in Greek as xenia and, in its specific relational form, xenía — occupies a distinctive position within the depth-psychology corpus as a structuring institution of the archaic Greek world that simultaneously encoded psychological, ethical, and cosmological imperatives. The corpus reveals the term operating on at least three registers. First, as a practical and ritual bond: Homer’s epics, above all the Iliad and Odyssey, present guest friendship as a network of obligations under the direct patronage of Zeus Xenios, violations of which carry theological as well as social consequences. Second, as an ethical threshold: scholarship by Cairns, Konstan, and Seaford illuminates how the host-guest relation was policed by aidos (shame), nemesis (righteous indignation), and kharis (reciprocal gratitude), making xenia an index of moral character. Third, as a site of proto-psychological reflection: the Glaukos-Diomedes episode in the Iliad shows guest friendship overriding enmity and regulating violence through the exchange of genealogical narrative and material tokens — a scene that ancient and modern commentators treat as exhibiting the integrative power of symbolic exchange. Tension runs throughout the corpus between the unconditional demand of xenia and the contingency of its performance, between its role as civilizational marker (those who welcome strangers versus ‘lawless aggressors’) and its susceptibility to exploitation and betrayal.