This course introduces international water law as a framework for the cooperative governance of shared water resources. It covers key global principles, conventions, and treaties, including the 1992 Helsinki Convention, the 1997 UN Watercourses Convention, and the 2008 Draft Articles on Transboundary Aquifers. The course also examines how these principles are applied in basin-specific contexts and explores the role of basin organizations in fostering long-term cooperation and peace.