Anton Friedrich Justus Thibaut (4 January 1772 – 20 March 1840), was a German jurist and musician.
He was born at Hamelin, in Hanover, the son of an officer in the Hanoverian army, of French Huguenot descent. After school in Hameln and Hanover, Thibaut entered the University of Göttingen as a student of jurisprudence, went from there to Königsberg, where he studied under Immanuel Kant, and afterwards to the University of Kiel, where he was a fellow-student with Niebuhr. Here, after taking his degree of doctor of laws, he became a Privat-dozent.
In 1798 he was appointed extraordinary professor of civil law, and in the same year appeared his Versuche über einzelne Theile der Theorie des Rechts (1798), a collection of essays on the theory of law, of which by far the most important was entitled Über den Einfluss der Philosophie auf die Auslegung der positiven Gesetze, wherein he sought to show that history without philosophy could not interpret and explain law. In 1799, he published his Theorie der logischen Auslegung des römischen Rechts, one of his major works. In 1802 he published a short criticism of Feuerbach's theory of criminal law, which recalls in many ways the speculations of Jeremy Bentham. The same year appeared Über Besitz und Verjahrung, a treatise on the law of possession and the limitation of actions.
In 1802 Thibaut was called to Jena, where he spent three years and wrote, in Friedrich Schiller's summer-house, his chief work, System des Pandektenrechts (1803), which ran into many editions. The fame of this book results from its being the first modern complete compendium of the subject, distinguished alike by the accuracy of its sources and the freedom and unpedantic manner in which the subject is handled. It is, in effect, a codification of the Roman law as it then obtained in Germany, modified by canon law and the practice of the courts into a comprehensive system of Pandect law. At the invitation of the grand-duke of Baden, Thibaut went to Heidelberg to fill the chair of civil law and to assist in organizing the university; and he never left the town, though in later years, as his fame grew, he was offered places at Göttingen, Munich and Leipzig. His class was large, his influence great; and, except Gustav Hugo and Savigny, no civilian of his time was so well known. In 1814 appeared his Civilistische Abhandlungen, of which the principal was his famous essay, the parent of so much literature, on the necessity of a national code for Germany (vide infra).