Middle Tennessee is a distinct portion of the state of Tennessee, delineated according to law as well as custom. Middle Tennessee consists of that portion of the state east of the Tennessee River's western crossing of the state (in which it flows northward back into Tennessee after having flowed through northern Alabama) and west of the dividing line between the Eastern and Central time zones. The only exceptions to this rule are that Hardin County, which is located on both sides of the Tennessee River, is considered to be entirely in West Tennessee and that Marion County is considered to be in East Tennessee despite lying in the Central Time Zone.

Middle Tennessee is known for its rolling hills and fertile stream valleys, as well as for its major city, Nashville. Other sizeable cities in Middle Tennessee include Clarksville and Murfreesboro. Politically, it has provided the Democratic Party with some of its leading statesmen, and still is largely inclined toward it, although an increasing Republican trend has been seen in recent years, particularly in the Nashville suburbs. Geographically it is composed predominantly of the Nashville Basin and the Highland Rim, although the western portion of the Cumberland Plateau also extends into Middle Tennessee.

Unlike the geographic designations of regions of most U.S. states, the term Middle Tennessee has legal as well as socioeconomic meaning. Middle Tennessee, along with West Tennessee and East Tennessee, comprises one of the state's three Grand Divisions. According to the state constitution, no more than two of the state supreme court's five justices can come from any one Grand Division. A similar rule applies to certain other commissions and boards as well, to prevent them from showing a geographic bias.