Simpsonville is a city in Greenville County, South Carolina, United States. It is part of the Greenville, SC Metropolitan Statistical Area. The population was 23,354 at the 2020 census, up from 18,238 in the 2010 census. Simpsonville is part of the "Golden Strip", along with Mauldin and Fountain Inn, an area which is noted for having low unemployment due to a diversity of industries including H.B. Fuller, KEMET, Sealed Air and Milliken. It is the 23rd-most populous city in South Carolina.