Sivaslı is a town located in the Uşak Province within the inner Aegean region of Turkey. It serves as the administrative seat of the Sivaslı District and has a recorded population of 7,082 as of 2022.
The town was formerly known as Sebaste. The ancient city area of Sebaste is situated approximately 2 kilometers, or 1.2 miles, from the modern town center of Sivaslı.