Stephen Kwelio Chemlany (born 9 August 1982) is a Kenyan long-distance runner who competes in the marathon. He has a personal best of 2:06:24 hours for the event.
Chemlany was runner-up at the 2011 Berlin Marathon and came fourth at the 2013 Berlin Marathon. He has won the Dalian Marathon (twice), the Tiberias Marathon and the Macau Marathon. He gained a master's degree in computer science from Iona College in the United States in 2008 and represented the school athletically.