Our modern age has modified somewhat the definition of “family” as a way of thinking about relationships between men and women, parents and children, and brothers and sisters. Plutarch did not imagine these relationships in terms of sexuality and gender. Rather, affection, love, marriage, and the family were the key concepts in his study of “private life.” He also lived, however, during an era of change. This change had consequences for the idea of marriage, justifying a more in-depth analysis of Plutarch’s view of the subject. In order to distinguish between contemporary attitudes and original ideas in his works, we will clarify the notion of “private life,” the philosophical tradition, and contemporary idea(s) of the family before reintegrating familial relations into Plutarch’s view of human nature and code of ethics.