This chapter proposes an understanding and theoretical framework for the research and study of international maritime law. This body of law has ancient origins and aims at universality and uniformity in regulation because shipping is global and transnational. The framework is set out in two interacting layers. First, there is an explanation of the nature of maritime regulation, definition, rationale, functions, instruments and regulatory bodies. Second, the principles of maritime regulation, regulatory process, rule-making strategies and regulatory compliance are set out and analysed. The focus is on the International Maritime Organization as the most important regulator and its complex regulatory regimes. The chapter provides insights into the structure and process of maritime regulation and offers an assessment of factors that facilitate or constrain universality and uniformity in this regulatory field.