Malcolm Klassen (born in Toekumsrus, Randfontein, South Africa) is a professional boxer in the junior lightweight (130 lb) division. Known as "Stone", he was a virtual unknown in the boxing world until he challenged and defeated Gairy Saint Clair for IBF world junior-lightweight title on 4 Nov 2006. He lost his belt in his first defense against unheralded Mzonke Fana.
Klassen lost a decision to Robert Guerrero on Aug. 22, 2009.
| Preceded by Gairy St. Clair |
IBF Junior Lightweight Champion November 4, 2006 – April 20, 2007 |
Succeeded by Mzonke Fana |
| Preceded by Cassius Baloyi |
IBF Junior Lightweight Champion April 18, 2009 – August 22, 2009 |
Succeeded by Robert Guerrero |