Recent discussion of global environmental assessment processes suggests that the process of consensus creation is central to understanding the way knowledge is produced and conclusions are reached. Here we contribute to this literature by providing a case study of the World Commission on Dams, which brought together supporters and opponents of large dams, at the height of controversy about dams in the 1990s. The Commission reviewed evidence and formulated guidelines for best practice, finding a way through a political stalemate. The article draws on interviews with those involved in the Commission and discusses the historical context, form of stakeholder representation, time horizon, and leadership style as consensus-enabling conditions. We conclude that an ambitious consensual process was successful within the life of the Commission, but at the cost of carrying external actors with it, leading to challenges with dissemination and uptake of consensual recommendations.