This book examines the environmental protection of transboundary lakes, with a particular focus on Lake Tanganyika. This lake, shared by four countries (Burundi, Democratic Republic of Congo, Tanzania and Zambia), represents a vital but vulnerable ecosystem in the face of environmental challenges and human impacts. It explores the international and regional legal frameworks governing the protection of transboundary lakes, including relevant conventions and treaties such as the Ramsar Convention, the Convention on Biological Diversity, and the Regional Agreement for the Management of Lake Tanganyika. It also analyzes the cooperation mechanisms and challenges encountered in implementing these instruments, highlighting governance aspects, legislative shortcomings and the need for integrated and sustainable management strategies. Finally, recommendations are made for improving the protection of Lake Tanganyika, including the strengthening of international cooperation, the effective implementation of existing agreements, and the adoption of stricter environmental policies by riparian states.