William Cheruiyot Sigei (born 11 October 1969 in Cheboi'ngong' village, just outside Kapsimotwo village, Bomet, Kenya) is a former Kenyan long-distance runner who won the IAAF World Cross Country Championships in 1993 and 1994.
In 1994 he set a new world record over 10,000 metres in Oslo with 26:52.23 minutes.
As of 2021[update], he is ranked thirty seventh of all times over 10,000 metres.
The current world record is 26:11.00 minutes, and belongs to Joshua Cheptegei of Uganda.
This Kenyan biographical article relating to athletics is a stub.