|Shifting science-society relationships are highly relevant both to contemporary practices of citizenship, their expressions, and to questions around the dynamics of “participation”. Political and economic changes are altering the contexts, spaces and ways that people perceive and act on citizenship rights, as are scientific and technological changes and the new risks and opportunities they present. Today these issues are reflected perhaps most clearly in the extensive academic, policy and media debates which explore contemporary relations between risk, science and society. In this paper we begin to explore these issues in a globally-comparative frame, providing a review of some of the dominant lines of work in Science and Technology Studies (STS) and Development Studies (DS) which reflect on the relationships between science and citizenship. First we consider major emphases in how each has conceived of the relationships between “experts” and “lay knowledges”, revealing some important contrasts in their approaches. We then go on to examine how different notions of citizenship have been incorporated into these debates, whether explicitly or implicitly. We show that approaches to participation and deliberation, now central to thinking and action in a scientific context in both north and south, are underlain by particular concepts of the citizen, which variously enable and constrain their transformative potential. Today these processes take place in a globalised context, and in a third section we reflect on how this context forces us to redefine further the relationships between science and citizenship. We show in this context why it is necessary to go beyond static, universalised and essentialised notions of citizenship and a singular notion of the state, to embrace a more fluid, de-centred, and experience-based notion of both citizenship and expertise, but without losing sight of the historical, political and institutional structures which shape often highly contrasting forms of engagement.