The eyalet of Aidin, also known as eyalet of Smyrna or Izmir (Ottoman Turkish: ایالت آیدین; Eyālet-i Āydīn) was an eyalet of the Ottoman Empire.
After the Janissary corps was abolished in 1826, the administrative divisions of the Empire were changed, and the Eyalet of Anatolia was divided into 4. In 1841, the capital was moved to İzmir, only to be moved back to Aydın in 1843. Three years later, in 1846, the capital was moved to Izmir once again. With the adoption of the vilayet law in 1864, the eyalet was re-created as the Vilayet of Smyrna.