Common-pool resources (CPRs) are critical in sustainability transitions. They are often important means for environmental and societal innovation, and object of unsustainable extraction and governance practices. We argue why CPRs and their governance matter in transitions and point to issues for further research: (i) conceptualization of sustainability and transitions in light of common-pool resources and governance; (ii) the roles, potentials, and challenges of commoning practices, beyond the market–state dichotomy; (iii) interactions between CPRs and commons with markets/firms and the state/governments in processes of sustainability transitions. These overarching questions bring fresh perspectives to transitions literature: (i) CPRs/commons help advance the integration between ecological and socio-technical systems (ii) nonexcludable resources affect entrepreneurial activity and innovation processes in the dynamics of socio-technical system; (iii) CPRs/commons add new viewpoints to the question of directionality of transitions. We conclude by advocating for building bridges with new institutional and environmental economics, and social practice theory.