Fall Branch is a census-designated place (CDP) in Washington and Greene counties in the U.S. state of Tennessee.

Fall Branch is part of the Johnson City Metropolitan Statistical Area, which is a component of the Johnson City–Kingsport–Bristol, TN-VA Combined Statistical Area – commonly known as the "Tri-Cities" region.

One of the earliest settlers at Fall Branch was Isaac White, a Revolutionary War veteran who arrived in the area in 1781.

The Joseph Sheppard House, constructed in the late 1850s, was believed to have been used to hide Confederate soldiers during the Civil War.

The Hopper House, used as a boarding home for early Fall Branch Seminary students, was constructed in the first half of the 19th century.

[12] Many of Fall Branch's houses and public buildings lie along the base of the 1,962-foot (598 m) Fulwiler Hill.

[13] Chimneytop Mountain, part of the greater Ridge-and-Valley Appalachians, rises prominently several miles to the west.

According to the United States Census Bureau, the CDP has a total area of 4.5 square miles (11.7 km2), all of it land.

The post office is located at 134 Ruritan Road, Fall Branch, Tennessee 37656.

West Pines Elementary School (grades PreK–8) previously served the Greene County portion until its closure in 2019.