This chapter looks at conflicts and peacebuilding in the Mediterranean region. Guided by a Historical International Political Sociology (HIPS) of modern world society it addresses conflicts and peacebuilding in the Mediterranean as phenomena that are simultaneously shaped by the internal as well as external dynamics of the region. This internal/external interplay is, in turn, subject to broader structures and cultures of world politics, generally speaking and what the English School of international relations refers to as international society, more specifically. This chapter is divided in three main sections. First, a short introduction into the main parameters of historical international political sociology (HIPS) with a particular focus on the English School concept of primary institutions of international society, illustrated with a view to selected examples from Mediterranean politics. Second, an ‘inside-out’ perspective that looks at how conflicts and peacebuilding play out on the basis of how the Mediterranean observes the world, i.e. how actors from the region appropriate, use and adapt primary institutions, such as self-determination, sovereignty, regional integration or human rights. Third, an ‘outside-in’ perspective that looks at the various forms of external interventions in and securitizations of the Mediterranean and how they in turn relate to primary institutions, i.e. how the world observes the Mediterranean.