Raphaël Lépine (6 July 1840 - 17 November 1919) was a French physiologist who was a native of Lyons.
From 1860 he served as interne at the hôpitaux de Lyon, and later moved to Paris, where from 1865 he worked as a hospital interne. In Paris he was a student of Jean-Martin Charcot (1825-1893). Afterwards he continued his education at the Universities of Berlin (1867) and Leipzig (1869). At Karl Ludwig's laboratory in Leipzig he performed important research on the vasomotor nerves of the tongue.
In 1870 he obtained his doctorate in Paris with a dissertation titled De l'hémiplégie pneumonique. At Paris he subsequently became chef de clinique (1872), médecin des hôpitaux (1874) and agrégé at the Paris Faculty (1875). In 1877 he was appointed professor of the medical clinic in the newly established medical faculty in Lyons.
Raphaël Lépine is known for his studies in experimental medicine, particularly his research involving the pathophysiology of diabetes, and his investigations of blood sugar and glycogenesis. He made important contributions in the study of internal secretions of the pancreas, and did extensive research of glycosuria. Among his written works were two influential works on diabetes called "Les complications du diabète et leur traitement" and "Le diabète non compliqué et son traitement".
He was the brother of Louis Lépine, Prefect of Police for the Seine from 1893 to 1897 and again from 1899 to 1913.