This chapter assess the philosophical foundation for Cicero’s views on human social relationships and community in the Roman Republic. Starting from De officiis 1.153, I argue that such a foundation is provided by the specifically Stoic notion of the community of gods and human beings, and of human beings as sharing rationality. The De officiis is then assessed on the basis of Cicero’s emphasis on the social aspect of virtue. The remainder of the chapter traces this same theme throughout Cicero’s theoretical writings (including his works on rhetoric), first in the earlier De inventione, De legibus, and De republica, and second in the De finibus and the Tusculanae Disputationes. Hence the commitment to this Stoic foundation for sociability is a constant in Cicero’s oeuvre.