The thesis focuses on how different forms of public participation have been conceived of, implemented and contested in the Lower Mekong River Basin. Through the case studies of Thailand and Cambodia, the thesis examines the public stakeholder consultations organised under the framework of the Mekong River Commission in relation to the mainstream Xayaburi, Don Sahong and Pak Beng dams, and how this came to be criticised as an unmeaningful process. First, the emergence of the stakeholder consultations, framed as domains for governmental intervention, are studied through a nuanced understanding of national institutional contexts. Second, the thesis examines how technical discourses and actors have come to dominate the consultations, and state attempts to render the process non-political. Through event ethnography, participatory spaces are studied both in terms of how power dynamics are generated through their physical dimensions and the ‘performances’ of state and nonstate actors. Third, the thesis considers the elements that constitute meaningful spaces of participation organised by civil society for local communities (emphasising the authority of community voices, accountability, and critical evaluation of technical information), and how these spaces are situated in multi-scalar political contexts. The analysis takes place through a conceptual framework that emphasises 1) rendering technical, 2) a co-produced, emergent and relational understanding of public participation, and 3) performativity. Overall, it is necessary to consider participant experiences in state and nonstate participatory spaces in relation to one another, and to create a wider and more nuanced understanding of what public participation encompasses. The thesis considers how this landscape of participation presents opportunities and challenges for wider public participation in Mekong hydropower governance.