Stefán Kristjánsson was an Icelandic chess player, awarded the titles of International Master (IM) in 1998 and Grandmaster (GM) in 2007 by FIDE. He was a Chess Olympiad participant, multiple-times participant in the European Team Chess Championships, and took part in FIDE World Cups.
Kristjánsson was born on December 8, 1982, in Reykjavík, Iceland. In the 2000 World Junior Chess Championship, he took 14th place in the U18 age group. He won the Icelandic Chess Championship in 2004 and the Icelandic Blitz Chess Championship in 2004 and 2006.
His participation in European Team Chess Championships involved representing Iceland in six competitions between 2003 and 2015. He also played for Iceland in four Chess Olympiads from 2004 to 2010.
Kristjánsson played in the FIDE Chess World Cups of 2005 and 2009. In 2005, he was eliminated in the first round by Sergey Dolmatov from Russia.
Kristjánsson ended his professional chess player career in 2015 and started working as a real estate agent.
On February 26, 2018, Kristjánsson died unexpectedly in his sleep at the age of 35. At the time of his death, he was the President of the Reykjavik Chess Academy. The cause of his death was a bacterial infection leading to an inflammation of the heart muscle.