The English republican writers of the seventeenth century, like their contemporaries of other political complexions, often simply assumed, rather than articulating or explicitly justifying, the exclusion of certain (large) categories of people from full participation in the political arrangements they proposed. Often it is only the use of incidental language – such as Milton’s language about masculinity or effeminacy – which reveals the unspoken assumption of the total exclusion of women from effective citizenship. Similarly, Harrington’s assumption that servants cannot be citizens is mentioned in such a brief and matter-of-fact way that it would be easy to miss. Indeed, it is easy for modern scholars to dismiss these persistent exclusions as the result of an understandable early modern blind-spot, inevitable given certain deeply-held early modern assumptions and norms. In fact, however, the exclusion of people from the category of effective citizenship was a persistent focus of anxiety in these republican texts. The examples of ancient and modern republics such as Sparta and Venice raised troubling questions about how restrictively the boundaries of citizenship could be drawn, and this caused particular debate as republicans such as Harrington, Stubbe and Neville argued over how these polities should be classified (were they aristocracies or democracies?). In this paper I will argue that these anxieties and disputes about the boundaries of the citizen body cast light on the republicans’ understanding of citizenship as a moral category, and that even the more categorical exclusions (such as of women, children, servants, or slaves) were bound up with the same set of moral arguments as those about more controversial exclusions from the citizen body. Indeed, discussion about the unworthiness of some (adult males) to be citizens often involved comparing them to women, children, or slaves, a rhetorical move which had the (unintended) effect of bringing these excluded categories back into discussions of citizenship in problematic ways.