Gainesboro is a town in Jackson County, Tennessee, United States. The population was 879 at the 2000 census. It is the county seat of Jackson County.
Gainesboro is part of the Cookeville, Tennessee Micropolitan Statistical Area.
Gainesboro is located at 36°21′35″N 85°39′17″W / 36.35972°N 85.65472°W / 36.35972; -85.65472 (36.359705, -85.654657), approximately 15 miles northwest of Cookeville.