Seagoville is a city in Dallas County, Texas, United States, and a suburb of Dallas. A small portion of Seagoville extends into Kaufman County. The population was 18,446 at the 2020 census. The city is located along U.S. Highway 175, 10 miles (16 km) from downtown Mesquite.

Dallas County is the second-most populous county in the U.S. state of Texas with a 2020 U.S. census of 2,613,539, making it the ninth-most populous county in the country. Dallas County is included in the Dallas-Arlington-Fort Worth metropolitan statistical area—colloquially referred to as the Dallas–Fort Worth metroplex. Municipal expansion within Dallas County has blurred the geographic lines between cities and between neighboring counties.