Friedrich Ranke (21 September 1882 - 11 October 1950) was a German medievalist philologist and folklorist. His Old Norse textbook Altnordisches Elementarbuch remains a standard, and all literature concerning Gottfried von Strassburgs Tristan und Isold uses Ranke's line numbering for references to the text.
Born in Lübeck as one of three sons of the theologian Leopold Friedrich Ranke and his wife Julie (von Bever) (1850–1924) he was a brother of the Egyptologists Hermann und Otto Ranke (1880–1917). Graduating from the Katharineum at Lübeck, he studied German, English and Nordic philology at the universities of Göttingen (1902/03), Munich (1903/05) and Berlin (1905/07). In Munich he studied with the pioneering folklorist Friedrich von der Leyen. In Berlin he made his publishing debut with Sprache und Stil im Wälschen Gast des Thomasin von Circlaria ("Language and style in 'The Romansh Guest' by Thomasin von Zirclaere"). His term at the University of Strassburg produced his work of German folktales, Der Erloser in der Wiege; ein Beitrag zur Deutschen Volkssagenforschung ("The Redeemer in the cradle: a contribution towards German folktale research", 1911).
From 1912 Ranke was occupied as a tutor in Göttingen, After returning from his service at the front in World War I he was appointed assistant professor there in German philology, and then in 1921 full professor in German philology at the University of Königsberg; in 1930 he occupied the same position at the University of Breslau, whence, silenced by the Nazis in 1937, he removed to the University of Basel, Switzerland, as professor of German philology, where he remained until his death.