State Route 338 (SR 338) is a secondary highway located entirely within Sevier County in East Tennessee.

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.

The entire route is in Sevier County.