The bilateral relations between Turkey and Azerbaijan are often described as brotherly and friendly in everyday life as well as by foreign policy elites as their societies share several close cultural and linguistic ties. The influence of kinship and friendship on states is becoming a field within International Relations, and these concepts can be fruitful to better understand relations between states by providing a perspective that is often taken for granted or not studied systematically. Theoretically, the thesis draws on discourse analysis to uncover how foreign policy elites categorise the world, their interpretation of meaning, and how they perceive and describe kinship and friendship. The objective of this study has been to explain how and to what extent Turkish and Azerbaijani elites are using claims of historical and metaphorical kinship to legitimise their bilateral relationship and conduct foreign policy. This is more specifically analysed by looking at the frozen conflict in Nagorno-Karabakh in the South Caucasus because it underlines the special character of the bilateral relations between Turkey and Azerbaijan, as Ankara has been supporting Baku’s position against Armenia. The temporal focus of the thesis spans primarily from 1991 until 2016, and a genealogical approach is adopted to attempt uncovering how Turkish and Azerbaijani foreign policy elites began to speak about each other in terms of kinship, and to which extent such discursive representations have become naturalised and dominant. The data material constitutes both written and oral texts and includes official foreign policy texts, such as speeches, press releases, and statements in addition to semi-structured interviews conducted in Turkey and Azerbaijan with academics and experts. The empirical analysis shows that Turkish and Azerbaijani elites started representing one another as kin after the Cold War, and that today, the concept seem to be naturalised in the foreign policy discourse, also in the context of the conflict in Nagorno-Karabakh. The analysis thus demonstrates how these discursive representations of kinship and friendship for the most part persists, and has become a significant part of their shared narrative or common story enforcing the affective character of inter-state relations. Furthermore, cultural and linguistic ties are important in facilitating the bilateral cooperation, and this partnership has mutual benefits for Turkey and Azerbaijan.