This book argues that there is an urgent need to reevaluate how international environmental law can enhance the ecological well-being of transboundary rivers. Through understanding the motivations behind river protection, the book identifies the cultural values associated with rivers and considers how these can be incorporated into international legal frameworks to enhance river protection. The book explores prominent cultural values, including aesthetic, heritage, Indigenous, and spiritual values, and presents ways in which these can be recognized through international water law, the sustainable development principle, and protected areas law. Adopting case studies of transboundary rivers worldwide, the book shows that implementing cultural values through international environmental laws can lead to improved ecological outcomes for the world’s transboundary rivers. This book will be of interest to students and scholars in the fields of environmental law, international water law, international legal theory, and freshwater conservation.