Bernard Kipchirchir Lagat (born December 12, 1974) is an American middle and long distance champion athlete.

Lagat was born in Kapsabet, Kenya. Prior to his change of domicile to the USA, Lagat had an extensive competitive career representing his native country.

He is the American record holder in the 1500m, mile, 3000m, and 5000m indoors, as well as the 1500m, 3000m, and 5000m outdoors, and is the Kenyan record holder at 1500m outdoors.

Lagat is a twelve time medalist in World Championships and Olympics including five gold medals.

Lagat, now a Kenyan American, was born in Kaptel village, near Kapsabet town in Nandi District. He is a Nandi, sub-tribe of the Kalenjin people.

He graduated from the Kaptel High School in 1994, where he had started his athletics career. He joined Jomo Kenyatta University of Agriculture and Technology in Nairobi 1996. Later in the same year he moved to Washington State University where other Kenyan athletic greats such as Henry Rono and Michael Kosgei prospered.

In 1998, while at WSU, Lagat won three NCAA individual championships; indoor mile and 3000m, as well as the 5000m outdoors.