Walter Borho (born 17 December 1945, in Hamburg) is a German mathematician, who works on algebra and number theory. Borho received his PhD in 1973 from the University of Hamburg under the direction of Ernst Witt with thesis Wesentliche ganze Erweiterungen kommutativer Ringe. He is a professor at the University of Wuppertal. Borho does research on representation theory, Lie algebras, ring theory and also on number theory (amicable numbers) and tilings.