Lothar Meyer (in full, Julius Lothar von Meyer) (1830-1895) was a German chemist.

Meyer was born in Varel, at that time belonging to the duchy of Oldenburg, now part of Germany. He qualified in medicine at Zürich, Switzerland. and then studied and taught at various German universities. His first interest was the physiology of respiration, and in 1857, he recognized that oxygen combines with the hemoglobin in blood.

In 1864 he produced an early version of the periodic table of chemical elements, which he expanded greatly in 1870, working completely independently of the Russian chemist Dmitry Ivanovich Mendeleev, but producing a virtually identical periodic table.

Meyer's contributions also included the concept that the carbon atoms in benzene were arranged in a ring, though he did not propose the alternation of single and double bonds that later became included in the structure by Kekulé.

In 1876, Meyer became the first Professor of Chemistry at the University of Tübingen, where he served until his death there.