ABSTRACT: This paper discusses Mill’s early essay on marriage and divorce (1832) and gives two possible sources of influence for it: Plato’s arguments on the appropriate scope of the law in book IV of his Republic and Unitarian ideas on motherhood. It demonstrates that Plato’s Republic and Mill’s essay both emphasize the crucial role of background conditions in achieving desirable social aims. Similar to Plato’s claim that the law should provide only a rough framework and not concern itself with questions of etiquette (Republic, 425d), Mill envisions a society in which men and women meet as equals and hence are in no need of marriage laws. Besides, this paper will relate Mill’s essay on marriage and divorce to Unitarian ideas on the social role of women to account for his reservations about the gainful employment of married women and mothers. Mill’s claim that the rightful employment of a mother is “the training of the affections” (Mill 1970, 76) is fueled by the Unitarian conception of women as the moral educators of future citizens.