Arnold Schönhage (born 1 December 1934 in Lockhausen, now Bad Salzuflen, Free State of Lippe) is a German mathematician and computer scientist.
Schönhage was professor at the Rheinische Friedrich-Wilhelms-Universität, Bonn, and also in Tübingen and Konstanz. He now lives near Bonn. Together with Volker Strassen he developed the Schönhage–Strassen algorithm for fast integer multiplication that has a run-time of O(N log N log log N).
Schönhage designed and implemented together with Andreas F. W. Grotefeld and Ekkehart Vetter a multitape Turing machine, called TP, in software. The machine is programmed in TPAL, an assembler language. They implemented numerous numerical algorithms including the Schönhage–Strassen algorithm on this machine.