Heinrich Friedrich Zimmer (December 11, 1851 - July 29, 1910) was a German Celticist and Indologist. He studied ancient languages at Kaiser Wilhelm University in Strassburg, going on to study Indology and Sanskrit under Rudolf von Roth at the University of Tübingen. In 1878 he became a lecturer at Friedrich Wilhelm University in Berlin; in 1881 he became Professor of Sanskrit and Comparative Linguistics at the University of Greifswald. In 1901 he became the founding Professor of Celtic at Friedrich Wilhelm University, the first position of its kind in Germany. In 1902 he became a member of the Prussian Academy of Sciences and in 1906 a corresponding member of the Bavarian Academy of Sciences and Humanities.