Kurt Werner Friedrich Reidemeister (October 13, 1893 – July 8, 1971) was a mathematician born in Braunschweig (Brunswick), Germany.
He received his doctorate in 1921 with a thesis in algebraic number theory at the University of Hamburg under the supervision of Erich Hecke. In 1923 he was appointed assistant professor at the University of Vienna. While there he became familiar with the work of Hans Hahn and Wilhelm Wirtinger. In 1925 he became full professor at University of Königsberg, where he stayed until 1933, when he was forced to leave because of his opposition of the Nazis.
Reidemeister's interests were mainly in combinatorial group theory, combinatorial topology, geometric group theory, and the foundations of geometry. His books include Knoten und Gruppen (1926), Einführung in die kombinatorische Topologie (1932), and Knotentheorie (1932). He was the brother of Marie Neurath.