Governance of transboundary water systems is complicated by factors such as institutional fragmentation, social and environmental change, competing values for and uses of water and power dynamics. These challenges exist in both international and federal transboundary contexts, although much of the scholarly attention has been on international transboundary watersheds. Sustainable transboundary water governance is an important goal given the fact that freshwater ecosystems are among the most rapidly degrading in the world. Governance, the ways in which decisions are made and implemented, can have a critical role to enable sustainability in transboundary watersheds. Many analyses of transboundary water systems provide only partial accounts of transboundary water governance because they focus primarily on the roles of governments and interjurisdictional institutions. Furthermore, analyses of federal transboundary water systems have not satisfactorily considered the role of power dynamics as possible constraints on transboundary water governance. Appreciation of the full complexity of transboundary water governance, and factors that constrain and enable sustainable transboundary water governance, requires considering governance processes at multiple levels and the variety of actors that may be involved therein. A power-analysis can facilitate consideration of which interests are advantaged in various governance processes that have implications for sustainable transboundary water governance. The purpose of this study is to explore factors that constrain and enable sustainable transboundary water governance in a federal transboundary water system. Explicitly assessing multi-level governance processes, and the ways in which power dynamics impact them, facilitates a consideration of their roles and contribution to transboundary water governance. This study's purpose is achieved via the following objectives: 1) identify the jurisdictional levels at which federal transboundary water governance takes place in the Mackenzie River Basin, (MRB), Canada; 2) consider the design and performance of an interjurisdictional river basin organization (RBO) in the MRB; 3) determine the ways in which power dynamics impact a) collaboration and b) water use decisions within jurisdictions in the MRB; and 4) assess the role and contribution of a) an RBO, b) collaboration and c) water use decisions within jurisdictions to transboundary water governance within the MRB.