Paul Johann Anselm Ritter von Feuerbach (14 November 1775 – 29 May 1833) was a German legal scholar. His major work was a reform of the Bavarian penal code which became a model for several other countries.

He was the father of the philosopher Ludwig Feuerbach and the mathematician Karl Wilhelm Feuerbach; and the grandfather of the painter Anselm Feuerbach.

He was born in Hainichen, near Jena. He received his early education at Frankfurt on Main, where his family had moved soon after his birth. At the age of sixteen, however, he ran away from home, and, going to Jena, was helped by relations there to study at the university. In spite of poor health and the most desperate poverty, he made rapid progress. He attended the lectures of Karl Leonhard Reinhold and Gottlieb Hufeland, and soon published some literary essays of more than ordinary merit.

In 1795 he took the degree of doctor of philosophy, and in the same year, though possessing little money, he married. It was this step which led him to success and fame, by forcing him to turn from his favourite studies of philosophy and history to that of law, which was repugnant to him, but which offered a prospect of more rapid advancement.

At 23 he came into prominence by a vigorous criticism of Thomas Hobbes' theory on civil power. Soon afterwards, in lectures on criminal jurisprudence he set forth his famous theory, that in administering justice judges should be strictly limited in their decisions by the penal code. This new doctrine gave rise to a party called Rigorists, who supported his theory. Von Feuerbach was the originator of the famous maxim nullum crimen, nulla poena sine praevia lege poenali: "There's no crime and hence there shall not be punishment if at the time no penal law existed"

In 1801 Feuerbach was appointed extraordinary professor of law without salary, at the University of Jena, and in the following year accepted a chair at Kiel, where he remained two years.

His chief work was the framing of a penal code for Bavaria. In 1804, he had moved from the University of Kiel to the University of Landshut, but, on being commanded by King Maximilian Joseph to draft a penal code for Bavaria (Strafgesetzbuch für das Königreich Bayern), in 1805 he moved to Munich where he was given a high appointment in the Ministry of Justice and was ennobled in 1808. The practical reform of penal legislation in Bavaria was begun under his influence in 1806 by the abolition of torture.