Nazilli is a municipality and district located in the Aydın Province of Turkey. Covering an area of 691 km², it serves as the second-largest city in the province, following the city of Aydın.
The town is situated approximately 47 km (29 mi) east of Aydın on the road leading to Denizli. As of 2022, Nazilli has a recorded population of 162,737 residents.