Simon Chemoiywo (born 20 April 1968) is a Kenyan former long-distance runner. He competed in track, cross country and road running. At the IAAF World Cross Country Championships he twice represented Kenya: in 1994 he was the runner-up and team champion, then helped retain the team title for Kenya at the 1995 race. In road events he was twice winner of both the Saint Silvester Road Race and Vancouver Sun Run. He made his marathon debut in 1998 and set his best of 2:10:35 hrs while winning the Prague Marathon.