The ideals that are central to action research are not often explicitly addressed in writing about action research and participation. This article argues for a more explicit dialogue about the ideals of participation and how those ideals relate to participatory practices. The lack of such a dialogue can obscure both the process of participation and the ends to which such processes are put. It offers a beginning to the conversation by drawing out the implications of five principles that underpin many of the justifications for participatory approaches, namely: community and community engagement, the change orientation of participatory research, issues of power and control, the ownership and construction of knowledge, and the combination of these principles as a form of critique of non-participatory approaches to research. The basis for, and critiques of, each of these principles are explored in turn. From these discussions a series of "participatory" challenges are posed for the discussion of the participatory features of action research.