When reviewing some of the current publications in the main journals in environmental psychology, such as Environment and Behavior and the Journal of Environmental Psychology, we find that Participatory-Action-Research (PAR) is a methodological strategy seldom used in the field. Given this absence, in this paper we will argue in favor of increasing its use because we think that it is an appropriate approach for addressing environmental issues. According to our point of view, PAR is suitable for fulfilling environmental psychology's goals, since it deals at a collective level with the topics, processes and problems faced by communities or other groups in a participatory and systematic way. In PAR people are not only involved in research but also in knowledge-construction and problem-solving. Since environmental problems usually affect groups of people, and these people normally are not aware of their role in the production and the solution of these problems, PAR provides them with an opportunity for engaging in critical reflection on such issues and on their role as social actors in this respect.