State Route 338 (SR 338) is a secondary highway located entirely within Sevier County in East Tennessee. The road runs generally south–north although like most roads in East Tennessee it has numerous winding turns.

SR 338 begins at an intersection with US 441/US 411/SR 35/SR 71 in Seymour. It winds its way northeast as Boyds Creek Highway to pass through Boyds Creek before entering Sevierville and coming to an intersection with SR 66 and the Great Smoky Mountains Parkway. SR 338 turns south and becomes concurrent with SR 66 to pass through a business district before leaving SR 66 and turning northeast onto Douglas Dam Road and leaving Sevierville. It continues northeast through farmland to pass through Alder Branch, where it becomes Old State Highway 66, before turning north and crossing the French Broad River just west of the Douglas Dam. SR 338 then continues north to come to an end at an intersection with SR 139.

The entire route is in Sevier County.

Location	mi	km	Destinations	Notes
Seymour	0.0	0.0	US 411 north / US 441 (Chapman Highway/SR 35 north/SR 71) – Sevierville, Knoxville US 411 south (Maryville Highway/SR 35 south) – Maryville	Southern terminus
Sevierville			SR 66 north (Winfield Dunn Parkway) to I-40 – Kodak	Southern end of wrong-way SR 66 concurrency
			SR 66 south (Winfield Dunn Parkway) – Downtown, Pigeon Forge, Gatlinburg	Northern end of wrong-way SR 66 concurrency
​			Bridge over the French Broad River
​	20.2	32.5	SR 139 (Douglas Dam Road) – Kodak, Dandridge	Northern terminus
1.000 mi = 1.609 km; 1.000 km = 0.621 mi       Concurrency terminus