This chapter explores the sociological dimension of kinship diplomacy and the importance of blood kinship as a cohesive factor in diplomatic interaction. Specifically, the chapter focuses on diplomacy as a functional ‘third culture’ and on diplomats as part of a self-referential group of peers. It is argued that while metaphorical kinship and family metaphors are certainly central to diplomacy, blood kinship has been underestimated as a cohesive factor in diplomatic interaction.