Louis-Antoine Ranvier (2 October 1835 – 22 March 1922) was a French physician, pathologist, anatomist and histologist, who discovered the nodes of Ranvier, regularly spaced discontinuities of the myelin sheath, occurring at varying intervals along the length of a nerve fiber.

Here he founded a small private research laboratory on Rue Christine along with fellow intern Victor André Cornil, and together they later offered a course in histology to medical students which involved the careful examination of tissues under a microscope.

Their course was unique in the time as microscopy had not been viewed favourably in medicine especially by Henri Ducrotay de Blainville (1777-1850) and Auguste Comte (1798-1857).

In 1867, Ranvier entered the Collège de France and worked as an assistant to Claude Bernard.

Some of his most notable students included Ferdinand-Jean Darier, Justin Marie Jolly, Joaquín Albarrán, Luis Simarro Lacabra, Joseph-Louis Renaut, and Fredrik Georg Gade.