Participatory research has long held within it implicit notions of the relationships between power and knowledge. Advocates of participatory action research have focused their critique of conventional research strategies on structural relationships of power and the ways through which they are maintained by monopolies of knowledge, arguing that participatory knowledge strategies can challenge deep-rooted power inequities. Other action research traditions have focused more on issues of power and knowledge within organisations, while others have highlighted the power relations between individuals, especially those involving professionals and those with whom they work. Drawing on a longer essay on ‘Power and Knowledge’, to be published in the Handbook of Action Research (Sage 2007), this article explores the ways in which advocates of participatory research have explored these issues, arguing that it is when participatory approaches to knowledge, action and learning are linked that they have the most potential to challenge power inequities.