<p><strong>This dissertation reveals that a process of “norm mediation” between domestic tribal norms and international norms occurred in the 1930-1934 and 1992-2000 processes of settlement of the Saudi-Yemen territorial and boundary conflict. The mediation of the exercise of the international norms of settlement of interstate territorial conflict upon the exercise of the domestic tribal norms of honour, asabiyyah, and al-sulh permitted the leaders of the Kingdom of Saudi Arabia and Yemen to settle their territorial and boundary conflict.</strong></p><p>The existing academic literature dedicated to the settlement of interstate territorial conflicts overlooks the role of norms in the processes of settlement in favour of rational and state-centric approaches. Furthermore, this body of literature tends to focus on the outcomes of the settlements rather than the processes that lead to such settlements. The role that domestic societies and their governance, especially borderland societies, may have played in the processes of settlement of interstate conflicts is overlooked.</p><p>The case of the Saudi Arabia and Yemen territorial conflict is not an exception. While tribes and Shaykhs have been important actors in both the respective state-building processes, their role in the settlements of the 20th-century Saudi-Yemen territorial conflict has been generally ignored by the existing scholarship on the conflict. This body of scholarship tends to focus on the outcomes of the various settlement processes rather than the processes themselves and argues that the decisions that led to the settlement of the dispute were made to protect the economic, diplomatic, and legal interests of each state. Contrastingly, this thesis considers the role of the domestic tribal norms of honour, asabiyyah, and al-sulh, and provides a new and more nuanced understanding of the 1930-1934 and 1992-2000 settlements of the Saudi-Yemen territorial and boundary conflicts. Through a method of historical explanation, this research relies on primary sources composed of diplomatic archives, on secondary literature in anthropology and political science, and offers an emic account of the processes of settlements of the 20th century Saudi-Yemen territorial conflict.</p><p>This thesis argues that the exercise of the domestic tribal norms constituted and regulated the processes of settlement in the form of a “social equilibrium” between the two states. The observation of the cessation of the hostilities, the implementation of egalitarian outcomes, and the restoration of honour in the settlements of the Saudi-Yemen territorial conflict account for the presence of a “social equilibrium” and the exercise of the domestic tribal norms of honour, asabiyyah, and al-sulh at the interstate level. Subsequently, this thesis shows that the heads of both states behaved as tribal leaders in the settlement of their territorial conflict.</p><p>This thesis contributes to the discipline of International Relations devoted to explaining the role of norms in interstate relations and to the particular field of International Relations in the Middle East. Often overlooked in favour of mainstream Western and Eurocentric approaches, this thesis shows that important bodies of literature emerging from Middle East history and politics are better suited to understanding regional interstate relations. Thus, this thesis emphasises the need to consider Middle Eastern perspectives and provides a new and more nuanced explanation of the settlement of the Saudi-Yemen territorial conflict and its related processes. Consequently, the process of “norm mediation” revealed in this research positions this thesis in the broader IR discipline and the Constructivist school dedicated to understanding the interplay of domestic and international norms.</p>