Martin Kneser (21 January 1928 – 16 February 2004) was a German mathematician.
His father Hellmuth Kneser and grandfather Adolf Kneser were also mathematicians.
He obtained his PhD in 1950 from Humboldt University of Berlin with the dissertation: Über den Rand von Parallelkörpern.
His advisor was Erhard Schmidt.
His name has been given to Kneser graphs which he studied in 1955.
He also gave a simplified proof of the Fundamental theorem of algebra.
Kneser was an Invited Speaker of the ICM in 1962 at Stockholm.
His main publications were on quadratic forms and algebraic groups.