This article investigates the concept of “private” in Thomas More's Utopia and its philosophical influences. More did not follow a particular philosophy but was an eclectic intellectual inclined to combine different philosophies useful to develop and express his thought. More's philosophical sources are therefore numerous and include, among others, Epicurus, Augustine, Aristotle, and Seneca. In this article, I focus on the presence of Cicero and Plato in Utopia and, through the analysis of the occurrences of the concept of “private,” demonstrate that when it comes to the themes of justice and property More takes into account Roman philosophy and in particular Cicero in order to describe his contemporary society. When, however, More refers to property and justice in Utopia, viz. the society that should serve as a model for the existing societies, he takes into account Greek philosophy, in particular Plato.