August Wilhelm von Hofmann (April 8, 1818 - May 5, 1892) was a German chemist.

Hofmann was born at Giessen. Not intending originally to devote himself to physical science, he first took up the study of law and philology at Göttingen, and the general culture he thus gained stood him in good stead when he turned to chemistry, the study of which he began under Justus von Liebig. When, in 1845, a school of practical chemistry was started in London, under the style of the Royal College of Chemistry , Hofmann, largely through the influence of the Prince Consort, was appointed its first director. It was with some natural hesitation that he, then a Privatdozent at Bonn, accepted the position, which may well have seemed rather a precarious one; but the difficulty was removed by his appointment as extraordinary professor at Bonn, with leave of absence for two years, so that he could resume his career in Germany if his English one proved unsatisfactory. Fortunately the college was more or less successful, owing largely to his enthusiasm and energy, and many of the men who were trained there subsequently made their mark in chemical history. But in 1864 he returned to Bonn, and in the succeeding year he was selected to succeed Eilhard Mitscherlich as professor of chemistry and director of the laboratory in Berlin University.

Hofmann's work covered a wide range of organic chemistry though with inorganic bodies he did but little. His first research, carried out in Liebig's laboratory at Giessen, was on coal-tar and his investigation of the organic bases in coal-gas naphtha established the nature of aniline. This substance he used to refer to as his first love, and it was a love to which he remained faithful throughout his life. His perception of the analogy between it and ammonia led to his famous work on the amines and ammonium bases and the allied organic phosphorus compounds while his researches on rosaniline, which he first prepared. It formed the first of a series of investigations on coloring matter which only ended with quinoline red in 1887.

The Hofmann rearrangement bears his namesake.