The Theory of Moral Sentiments is a 1759 book by Adam Smith. It provided the ethical, philosophical, psychological, and methodological underpinnings to Smith's later works, including The Wealth of Nations (1776), Essays on Philosophical Subjects (1795), and Lectures on Justice, Police, Revenue, and Arms (1763) (first published in 1896). Broadly speaking, Smith followed the views of his mentor, Francis Hutcheson of the University of Glasgow, who divided moral philosophy into four parts: Ethics and Virtue; Private rights and Natural liberty; Familial rights (called Economics); and State and Individual rights (called Politics).

Hutcheson had abandoned the psychological view of moral philosophy, claiming that motives were too fickle to be used as a basis for a philosophical system. Instead, he hypothesised a dedicated "sixth sense" to explain morality. This idea, to be taken up by David Hume (see Hume's A Treatise of Human Nature), claimed that man is pleased by utility.

Smith rejected his teacher's reliance on this special sense. Starting in about 1741, Smith set on the task of using Hume's experimental method (appealing to human experience) to replace the specific moral sense with a pluralistic approach to morality based on a multitude of psychological motives.