This paper examines Catharine Trotter Cockburn’s moral philosophy, focusing on her accounts of virtuous conduct, conscience, obligation, and moral character. I argue that Cockburn’s account of virtue has two interlocking parts: a view of what virtue requires of us, and a view of how we come to see this requirement as authoritative. I then argue that while the two parts are ultimately in tension with one another, the tension is instructive. I use Cockburn’s encounter with Shaftesbury’s writings to help bring out this tension in her thought. I conclude that Cockburn’s work marks a bridge in modern moral philosophy from seventeenth-century natural law theory to the naturalism of the eighteenth century— that of Gay, Hume, and Bentham.