Stefan Remco Aartsen (born March 13, 1975, in 's-Gravenzande) is a former butterfly swimmer from the Netherlands, who twice competed for his native country at the Summer Olympics: in 1996 and 2000.
Aartsen first gained attention in 1992, when he won the title in the 200 m freestyle at the European Junior Championships in Leeds. In 1998 he was a member of the Dutch winning relay team (4×50 m freestyle) at the European Short Course Swimming Championships 1998 in Sheffield. A year later he won the gold medal in the 4×100 m medley relay at the European LC Championships 1999 in Istanbul, Turkey, alongside Klaas-Erik Zwering, Marcel Wouda and Pieter van den Hoogenband. After missing the 2004 Summer Olympics he retired in the spring of 2005.