He ran at the 2011 Great Edinburgh Cross Country in January, taking second place in the short race behind Eliud Kipchoge. Later that year he became world champion over 1500 m, defeating his Kenyan rival, Silas Kiplagat at the 2011 World Championships in Athletics. Kiprop ran the final 800 meters of the race well under 1:50 and the final 400 meters in 51 seconds plus. Kiprop was leading in the rankings of the 2011 IAAF Diamond League, having won at the Bislett Games Dream Mile and placed second at the Shanghai, Paris and Stockholm meets. However, at the event final at the Weltklasse Zürich, he managed only seventh while Nixon Chepseba won to take the seasonal title.