Transboundary watercourses, including rivers, lakes and aquifers (confi ned and unconfi ned), shared between two or more countries, are home to over 70 % of the world's population and supply water for roughly 60 % of global food production. It is no surprise that the management of these watercourses has been entrusted to national states, which have the power to take sovereign decisions over their management, use and conservation. State sovereignty is mitigated through the existence of a global institutional framework comprised of customary international water law (the norms dictating how states behave), global and regional conventions, basin-level agreements and basin management organisations. The good news is that there is a large body of joint institutions between countries with transboundary watercourses, the UN estimating that around 3600 exist. This in part explains the relative lack of military interstate confl icts. Less good news is that despite the existence of international-and basin-level agreements and basin organisations, the benefi ts to be expected from international cooperation around transboundary watercourses have in most cases not materialised. Acute, persistent and seemingly intractable problems persist, with ecosystem degradation not being reversed, joint investments in water infrastructure not materialising and joint management organisations failing to attract signifi cant long-term support from the respective basin states. Despite at least two decades of concerted support by the international development community, the impacts of enhanced interstate cooperation are noticeable through their absence. This chapter investigates why this may be so and introduces a starting point which moves beyond the state-centric approach to transboundary water management. In doing so it does not challenge the sovereign right of states to manage their watercourses; instead it shows how a range of non-state actors do in fact infl uence state practice through a variety of mechanisms. As these mechanisms are frequently covert, it becomes diffi cult to assess the integrity of the relationships between actors, in turn making public engagement and participation diffi cult. Needed is a governance paradigm which opens the decision-making arena to non-state actors all in support of the national governments and their respective mandates. This chapter ends with an indication of what such a governance arrangement