Isiah Kiplangat Koech (born 19 December 1993) is an Kenyan long-distance runner who specialises in the 5000 metres.At the 2009 World Youth Championships in Athletics in Brixen, Italy, Koech won a gold medal over 3000 metres, setting a new world youth leading time with 7:51.51.He also took part in the 2010 IAAF World Cross Country Championships in Bydgoszcz, Poland, finishing fourth in the junior men's race.On 11 February 2011, Koech became just the fourth man to run the 5000 m indoor under 13 minutes when he clinched victory in 12 min 53.29 sec at the PSD Bank Meeting in Düsseldorf.