John Stuart Mill's Utilitarianism is a philosophical defense of utilitarianism, a moral theory stating that right actions are those that tend to promote overall happiness. The essay first appeared as a series of articles published in Fraser's Magazine in 1861; the articles were collected and reprinted as a single book in 1863. Mill discusses utilitarianism in some of his other works, including On Liberty and The Subjection of Women, but Utilitarianism contains his only sustained defence of the theory.

In this edition, Colin Heydt provides a substantial introduction that will enable readers to understand better the polemical context for Utilitarianism. Heydt shows, for example, how Mill's moral philosophy grew out of political engagement, rather than exclusively out of a speculative interest in determining the nature of morality. Appendices include precedents to Mill's work, reactions to Utilitarianism, and related writings by Mill.