Open government and open data are new areas of research, advocacy and activism that have entered the governance field alongside the more established areas of transparency and accountability. This article reviews recent scholarship in these areas, pinpointing contributions to more open, transparent, accountable and responsive governance via improved practice, projects and programmes. The authors set the rest of the articles from this IDS Bulletin in the context of the ideas, relationships, processes, behaviours, policy frameworks and aid funding practices of the last five years, and critically discuss questions and weaknesses that limit the effectiveness and impact of this work. Identifying conceptual ambiguity as a key problem, they offer a series of definitions to help overcome the technical and political difficulties this causes. They also identify hype and euphemism, and offer a series of conclusions to help restore meaning and ideological content to work on open government and open data in transparent and accountable governance.