This paper outlines an institutionalist political economy approach to capitalism as a specific type of social order. Social science institutionalism considers social systems to be structured by sanctioned rules of obligatory behaviour. Its perspective is one of collective ordering, or governance, through regularization and normalization of social action, either by public authority or by private contract. Political economy looks at the interrelations between collective action in general, and collective rule-making in particular, and the economy; it extends from economic and social policy-making to the way in which economic interests and constraints influence policy, politics and social life as a whole. The approach proposed in this article looks at society and economy as densely intertwined and closely interdependent, which is exactly what traditional concepts of capitalism stood for. Proceeding from an institutionalist perspective, it elaborates a concept of capitalism not as a self-driven mechanism of surplus extraction and accumulation governed by objective laws, but as a set of interrelated social institutions, and as a historically specific system of structured as well as structuring social interaction within and in relation to an institutionalized social order.