Disputes over pollution, water quality, water rights, water diversions, and exports have played out along the Canada–U.S. border since the international border was first demarcated. In response, over the past 100 years, distinct types of transboundary institutions have emerged to address disagreements and facilitate exchange of information. This chapter provides an introductory overview and analysis of four transboundary institutions, operating at different scales, that govern water along the Canada–U.S. border: the International Joint Commission (IJC), the North American Free Trade Agreement’s Commission for Environmental Cooperation (CEC), the British Columbia–Washington Environmental Cooperation Council (ECC), and the Yukon River Inter-Tribal Watershed Council. Analyzing these transboundary institutions provides insight into how governance processes operate at different scales, and through different frameworks, mechanisms, and guiding principles.