Drawing on ethnographic research with social movement networks in Spain, this article explores the challenges and possibilities of research collaboration. My project focused on the emerging logics and practices of collective action, the ongoing re-definition of grassroots politics. The engagement with social movements as reflexive communities – not simply objects to be studied, but subjects actively producing their own analysis and explanations, their own ‘knowledge-practices’ – deeply transformed the in-fieldwork encounter. Through a series of co-analysis workshops, designed and implemented together with the research subjects/collaborators, this research became an open-ended dialogue of reflexivities. The shift from working on social movements to working and thinking together with social movement activists as co-researchers produced new scholarly knowledge, advancing our understanding of contemporary collective action, while simultaneously making research useful for the activists. Moreover, locating epistemic and methodological questions at the centre of the project, I addressed salient debates in social science, exploring collaborative frameworks in order to problematize traditional forms of knowledge production and validation.