Walter David Neumann (born 1 January 1946) is a British mathematician who works in topology, geometric group theory, and singularity theory. He is a professor at Barnard College, Columbia University. Neumann obtained his Ph.D. under the joint supervision of Friedrich Hirzebruch and Klaus Jänich at the University of Bonn in 1969.^[1]

Neumann in 1973

He is a son of the mathematicians Bernhard Neumann and Hanna Neumann.^[1] His brother Peter M. Neumann was also a mathematician.

He is in the Inaugural Class of Fellows of the American Mathematical Society.^[2]