Leon Abgarovich Orbeli (Armenian: Լևոն Աբգարի Օրբելի, Levon Abgari Orbeli; Russian: Леон Абгарович Орбели, Levon Abgarovich Orbeli; 7 July [O.S. 25 June] 1882 – 9 December 1958) was an Armenian physiologist active in the Russian SFSR. He was a member of the Academies of Science of USSR and Armenian SSR (the latter was founded by his brother Joseph Orbeli). Leon Orbeli became director of the Institute of Physiology in 1950.