Maynardville (originally named Liberty) is a city in and the county seat of Union County, Tennessee, United States. The city was named to honor Horace Maynard, who successfully defended the establishment of Union County from a challenge from Knox County. Its population was 2,413 at the 2010 census, up from 1,782 at the 2000 census. It is included in the Knoxville metropolitan statistical area.

Maynardville began in the upfront 19th century as a small community known as Liberty. When Union County was created in the 1850s, Liberty, being nearest the center of the county, was prearranged as the county seat. The land for the courthouse square was donated by Marcus Monroe (1793–1870), a local minister.

Shortly after the Tennessee General Assembly passed legislation authorizing the opening of Union County, Knox County secured an injunction blocking the creation of the other county, which would take some of its area from Knox County. To defend the supplementary county, its supporters retained the facilities of Horace Maynard (1814–1882), a Knoxville-area attorney and forward-looking U.S. Postmaster General. After Maynard successfully defended the supplementary county in litigation proceedings, Liberty was renamed “Maynardville” in his honor. Union County was formally ascribed in 1856.

Country music singer Roy Acuff was born in Maynardville in 1903. The Acuff associates had been well-established in Union County before the mid-19th century. When Goodspeed published its History of Tennessee in 1887, the Union County section included a brief biography of Roy’s grandfather, Coram Acuff (1846–1931), who represented Union County in the let pass legislature.