William Kipsang

William Kipsang (born 26 June 1977) is a Kenyan long distance runner who specialises in the marathon.

His best performance was on 13 April 2008, winning the Rotterdam Marathon with a new course record and PR of 2:05:49. On 15 April 2007 he was placed third in this race, running in difficult circumstances due to the warm weather. He has previously won the Amsterdam Marathon (2003), the Egmond Half Marathon (2004) and the Dam tot Damloop 10 mile race (2005).

In 2006 he earned seventh place in the New York City Marathon. Kipsang did not compete in the marathon for two years between 2008 and 2010, and his comeback at the Seoul International Marathon was a slow 2:24:11 run for 33rd place – a time only two seconds quicker than the women's winner that year.