Semirom County (Persian: شهرستان سمیرم) is in Isfahan province, Iran. Its capital is the city of Semirom.
At the 2006 census, the county's population was 70,735 in 17,072 households. The following census in 2011 counted 65,047 people in 18,062 households. At the 2016 census, the county's population was 74,109 in 22,530 households,by which time, Vardasht Rural District had been separated from the Central District in the establishment of Vardasht District, and Padena-ye Olya Rural District had been separated from Padena District in the establishment of Danakuh District