The Cimmerians were an ancient Eastern Iranic equestrian nomadic people originating in the Pontic–Caspian steppe, part of whom subsequently migrated into West Asia. Although the Cimmerians were culturally Scythian, they formed an ethnic unit separate from the Scythians proper, to whom the Cimmerians were related and who displaced and replaced the Cimmerians.

The Cimmerians themselves left no written records, and most information about them is largely derived from Neo-Assyrian records of the 8th to 7th centuries BC and from Graeco-Roman authors from the 5th century BC and later.

The English name Cimmerians is derived from Latin Cimmerii, itself derived from the Ancient Greek Kimmerioi (Κιμμέριοι), of an ultimately uncertain origin for which there have been various proposals:

The name of the Cimmerians is attested in:

The Late Babylonian scribes of the Achaemenid Empire used the name "Cimmerians" to designate all the nomad peoples of the steppe, including the Scythians and Saka.

However, while the Cimmerians were an Iranic people sharing a common language, origins and culture with the Scythians and are archaeologically indistinguishable from the Scythians, all sources contemporary to their activities clearly distinguished the Cimmerians and the Scythians as being two separate political entities.

In 1966, the archaeologist Maurits Nanning van Loon described the Cimmerians as Western Scythians, and referred to the Scythians proper as the Eastern Scythians.

There are three main sources of information on the historical Cimmerians: