Friedrich "Fritz" Heinrich Lewy (/ ˈlɛvi/; January 28, 1885 – October 5, 1950), known in his later years as Frederic Henry Lewey, was a German-born American neurologist. He is best known for the discovery of Lewy bodies, which are a characteristic indicator of Parkinson's disease and dementia with Lewy bodies. In a 1912 paper based on work in Alois Alzheimer’s Munich laboratory he described intraneuronal inclusion bodies in brainstem nuclei of patients with paralysis agitans that were later termed Lewy bodies.
Lewy was born to a Jewish family in Berlin, Germany, on January 28, 1885. He trained in Berlin and Zürich and graduated from Berlin in 1910. He worked in Alois Alzheimer's Munich laboratory and was contemporary with Hans Gerhard Creutzfeldt (1885–1964), Alfons Maria Jakob (1884–1931) and Ugo Cerletti (1877–1963). In 1933, he fled Nazi Germany and moved to the United States. Lewy died in Haverford, Pennsylvania, on October 5, 1950, aged 65.