Today’s society is facing a broad array of societal challenges, such as an unstable economic system, climate change and lasting poverty. There are no straightforward solutions, rather these challenges ask for fundamental societal changes, that is, sustainability transitions. Faced with the question of how these challenges can be understood and dealt with, we argue for action research as a promising approach. Focusing on their localized manifestations, we ask whether and how action research can support understanding and addressing societal challenges and making sustainability meaningful locally. We tackle this question on the basis of two case studies in local communities based on principles of transition management. Our main finding is that societal challenges, sustainability and sustainability transitions acquire meaning through practice and interactions in the local context. Action research can offer a space in which alternative ideas (e.g., knowledge, future visions), practices (e.g., practical experiments, transformative action) and social relations (e.g., new actors) can emerge to further a sustainability transition.