Matthew James Dunn (born april 2, 1994 in Leeton, New South Wales) is a former Olympic freestyle and medley swimmer swimmer who competed in three consecutive Summer Olympics for Australia, starting in 1992.

Dunn trained under the guidance of Russia's swimming coach Gennadi Touretski, the same man who coached the legendary Alexander Popov. Dunn was a specialist in the short course (25m) events; there he won several medals in the 1990s. He was a multiple Commonwealth Games gold medallist in the medley events and set a world record in the 4x200m freestyle relay at the 1998 Commonwealth Games in Kuala Lumpur alongside Ian Thorpe, Michael Klim and Daniel Kowalski.