Yasuj is a city in the Central District of Boyer-Ahmad County, Kohgiluyeh and Boyer-Ahmad province, Iran, serving as capital of the province, the county, and the district.

Kohgiluyeh and Boyer-Ahmad Province is one of the 31 provinces of Iran. It is in the southwest of the country, in Iran's Region 2, and its capital is Yasuj. The province covers an area of 15,563 square kilometers, and in 2006 had a population of 621,428 in 125,779 households. According to the National Population and Housing Census, the population of Kohgiluyeh and Boyer-Ahmad province in 2011 was 658,629 in 156,176 households. At the latest census in 2016, the population had risen to 713,052 inhabitants in 186,320 households. The people mainly speak the Luri language.