Our economies are no longer fit for purpose. They are driving the interlinked inequality, climate and biodiversity crisis and need to be upgraded, overhauled and transformed. This will require multi-level and multi-sectoral economic transformations, including new systems and institutions of economic governance. This chapter explores the potential of participatory mechanisms as a catalyst for deepening the social mandate for economic transformation and boosting the movement for new eco-social contracts for economic reform. It describes key institutional mechanisms that could be employed to engage and centre people in advocating for societies and economies that are greener and fairer, but also democratic and inclusive. Of these, five key mechanisms are proposed as a conduit for amplifying the social mandate for a just and sustainable economy: citizen assemblies, participatory budgeting, just transition processes, citizen dialogues, climate commissions and advisory councils. These mechanisms, and others like it, need to be rooted in broader democratic renewal to strengthen trust, accountability and transparency in eco-social contracts for economic transformations.