Lydian is an extinct Indo-European Anatolian language spoken in the region of Lydia, in western Anatolia. The language is attested in graffiti and in coin legends from the late 8th century or the early 7th century to the 3rd century BCE, but well-preserved inscriptions of significant length are so far limited to the 5th century and the 4th century BCE, during the period of Persian domination. Thus, Lydian texts are effectively contemporaneous with those in Lycian.

Lydia was an Iron Age kingdom situated in the west of Asia Minor, in modern-day Turkey. The ethnic group inhabiting this kingdom are known as the Lydians, and their language as Lydian and their capital was Sardis.