The Parni (/ˈpɑːrnaɪ/; Ancient Greek: Πάρνοι, Parnoi), Aparni (/əˈpɑːrnaɪ/; Ἄπαρνοι, Aparnoi) or Parnians were a Dahae tribe that, in the middle of the 3rd century BCE, invaded Parthia, where they founded the Arsacid dynasty. In the words of Lukas de Blois and Bert van der Spek, the Parni "drove away the Greek satraps, who had then only just acquired independence, and founded a new dynasty".[1] At that point in time, the Parni spoke an Eastern Iranian language,[2][3] although little is known about the ethnolinguistic affiliation of the Dahae, and they may previously have spoken a non-Iranian language.
Prior to their invasion of Parthia, the Parni lived around the Ochus (Panj) and Hari (Tejen) rivers, southeast of the Caspian Sea.[4][3][5] However, it is believed that their original homeland may have been in the Pontic Steppe (now southern Russia), from where they emigrated alongside, or as part of, Scythian tribes.[3]