Social institutions are complex social forms that reproduce themselves such as governments, police organizations, universities, hospitals, business corporations, markets, legal systems. Moreover, social institutions are among the most important of collective human phenomena; they enable us to feed ourselves (markets and agribusinesses), to protect ourselves (police and military services), to educate ourselves (schools and universities), and to govern ourselves (governments and legal systems).Sometimes the term institution is used to refer to complex social forms that are arguably not organizations such as human languages or kinship systems. However, my concern is only with institutions that are also organizations and/or systems of organizations.In this chapter I will offer a teleological normative theory of social institutions which is based on an individualist theory of joint action (Much of the content in this chapter is a highly condensed version of parts of Miller (The moral foundations of social institutions: a philosophical study. New York: Cambridge University Press, 2010)). Put simply, on this account social institutions are organizations or systems of organizations that provide collective goods by means of joint activity. The collective goods in question include the fulfilment of aggregated moral rights, such as needs based rights for security (police organizations), material well-being (businesses operating in markets), education (universities), governance (governments) and so on.