ABSTRACT This paper reconstructs William of Ockham's (c. 1287–1347) account of the ontology of social groups. Across his writings, Ockham mentions kingdoms, religious orders, crowds, people, armies, and corporations. Using the political community as a case-study against the background of Ockham’s metaphysics of parts and wholes, it is argued that at least some social groups are identical to a plurality of many human beings who have decided to order themselves with respect to another in some particular way. In this regard, (...) a social group is a structured aggregate that is nothing over and above its existing and ordered parts, and, at least in the case of the political community, is like an artefact inasmuch as it is partly dependent on the volitional acts of its members to exist at all. (shrink)