We offer a microfoundation of social entrepreneurship through the work of Vincent and Elinor Ostrom on polycentricity (Ostromian polycentricity) and that of Friedrich Hayek on the economics of knowledge (Hayekian knowledge) that reveals both the main strength and main weakness of social entrepreneurship. Problematizing social entrepreneurship in terms of the political economy of knowledge and based on Ostromian polycentricity and Hayekian knowledge, we first find the main strength of social entrepreneurship is that local, decentralized social entrepreneurs usually are the most appropriate and best-positioned—indeed, the most efficient—actors to solve their communities’ social problems. Also based on the work of the Ostroms and Hayek, we identify the main weakness of social entrepreneurship: the lack of institutional safeguards to social entrepreneurship. The localized decision-making process, however, might mitigate to some degree the potential for large-scale abuse.