Marc Charles Nicolas Duez (born 18 April 1957 in Verviers) is a racing and rally driver from Belgium.
Duesz won the 24 Hours of Nürburgring 4 times (1992, 1995, 1998 & 1999), the 24 Hours Spa three times (1997, 1998 & 2001) and the 24 Hours of Zolder two times (2000 & 2006).
Duez also has competed in the 24 Hours of Le Mans, scoring 4 class podiums, and the Andros Trophy.
For years now, Duez has been a representative for the RACB , the Royal Automobil Club of Belgium. He strongly promotes the Driver's Academy and the Belgian Racing Circuits.
Also since 2009, Duez has been racing for Fun Still Exists, also known as FSE. For this team, he has been racing the Legend Boucles de Spa 2010 and Ypres Historic Rally 2010, and also the Legend Boucles de Spa 2011.