Moral Theology (also known as the Theologia Moralis) is a nine-volume work concerning Catholic moral theology written between 1748 and 1785 by Alphonsus Liguori, a Catholic theologian and Doctor of the Church. This work is not to be confused with Theologia moralis universa ad mentem S. Alphonsi, a 19th-century treatise by Pietro Scavini written in the philosophical tradition of Alphonsus Liguori.^[1]

Nine editions of Moral Theology were published during the author's lifetime, the first of which was released in 1748 and consisted of annotations on a treatise called Medulla Theologiae Moralis by Hermann Busenbaum, a 17th-century Jesuit theologian. After the eighth edition in 1779, Alphonsus considered his work definitive, and in 1785 the ninth edition finalized the book's contents.^[2] Since his death, many further editions have been published, including a partially completed English edition from Mediatrix Press, the first volume of which was released in 2017.

The contents of each volume of Moral Theology are listed broadly below:^[3]

• Volume 1: Preface to the discourse (dissertatio prolegomena), on conscience, on laws, on the theological virtues, and on the first commandment
• Volume 2: On commandments II, III, IV, V, VI, IX and VII, on justice and laws, and on restitution
• Volume 3: On contracts, on commandments VIII, IX (again) and X, on the precepts of the church, and on the precepts of the individual
• Volume 4: On the canonical hours, on human actions, on sins, on the sacraments in general, and on Baptism and Confirmation
• Volume 5: On the Eucharist, on the sacrifice of the mass, and on Penance
• Volume 6: On Penance (continued), on Extreme Unction, on Holy Orders, and on Matrimony
• Volume 7: On Matrimony (continued), and on judgments and irregularities
• Volume 8: On the practice of confessions, examination of ordinands, summary of moral doctrines and canons from the works of Benedict XIV
• Volume 9: Episcopal decrees, appendices, general index

Mid-19th century and later editions may also include prefatory documents concerning Liguori's life, his beatification and canonization, or his recognition as a Doctor of the Church.

Catholic moral theology