Stefan Groothuis (born 23 November 1981 in Empe, Gelderland) is a Dutch speed skater. He is the World Sprint Champion for 2012.
Groothuis is a specialist in the middle distances, 1000 and 1500 metres and had his international breakthrough in 2005. In that year he reached a second spot during the Speed Skating World Cup meeting in Salt Lake City over 1000 metres. This earned him a nomination for the 2006 Winter Olympics in Turin. During the Dutch Single Distance Championships in December 2005 he switched this nomination into a qualification by becoming fourth behind Jan Bos, Erben Wennemars and Beorn Nijenhuis who all qualified as well.
In January 2006 Groothuis surprised by becoming the Dutch national sprint champion finishing in first position after two races over 500 metres as well as two over 1000 metres, outsprinting common names like Gerard van Velde, Nijenhuis and Wennemars. A month later at the 2006 Winter Olympics Groothuis would finish in 8th position over 1000 metres. His time of 1:09.57 was 0.68 behind on winner Shani Davis.
At the 2012 World Sprint Speed Skating Championships in Calgary, Groothuis won the gold medal. His points total of 136.810 broke the world record for the sprint combination held by Jeremy Wotherspoon.