Najafabad County () is in Isfahan province, Iran. Its capital is the city of Najafabad.
After the 2006 National Census, the village of Jowzdan was elevated to the status of a city.
At the time of the 2006 census, the county's population was 279,014 in 73,711 households. The following census in 2011 counted 300,288 people in 87,481 households. The 2016 census measured the population of the county as 319,205 in 98,513 households.
Najafabad County's population history and administrative structure over three consecutive censuses are shown in the following table.