Anahita is the Old Persian form of the name of an Iranian goddess and appears in complete and earlier form as 'Aredvi Sura Anahita', the Avestan name of an Indo-Iranian cosmological figure venerated as the divinity of "the Waters" (Aban) and hence associated with fertility, healing and wisdom.

The Greek and Roman historians of classical antiquity refer to her either as 'Anaïtis' or identified her with one of the divinities from their own pantheons. Based on the development of her cult, she was described as a syncretistic goddess, who was composed of two independent elements. The first is a manifestation of the Indo-Iranian idea of the Heavenly River who provides the waters to the rivers and streams flowing in the earth, while the second is that of a goddess of uncertain origin, though maintaining her own unique characteristics, who became associated with the cult of the ancient Mesopotamian goddess Inanna-Ishtar. According to one theory, this arose partly from a desire to make Anahita part of Zoroastrianism following the diffusion of her cult from the extreme northwest into the rest of Persia.

According to H. Lommel, the proper name of the divinity in Indo-Iranian times was Sarasvatī, which also means "she who possesses waters". In Sanskrit, the name आर्द्रावी शूरा अनाहिता (Ārdrāvī śūrā anāhitā) means "of the waters, mighty, and immaculate". Like the Indian Sarasvatī, Anāhitā nurtures crops and herds; and she is hailed both as a divinity and as the mythical river which she personifies, "as great in bigness as all these waters which flow forth upon the earth" (Yasht 5.3).

Conflation with Ishtar

At some point prior to the 4th century BC, this yazata was conflated with (an analogue of) Semitic Ištar, likewise a divinity of "maiden" fertility and from whom Aredvi Sura Anahita then inherited additional features of a divinity of war and of the planet Venus or "Zohreh" in Arabic. It was moreover the association with the planet Venus, "it seems, which led Herodotus to record that the [Persis] learnt 'to sacrifice to "the heavenly goddess"' from the Assyrians and Arabians." There are sources who based their theory on this aspect. For instance, it was proposed that the ancient Persians worshiped the planet Venus as *Anahiti, the "pure one", and that, as these people settled in Eastern Iran, *Anahiti began to absorb elements of the cult of Ishtar. Indeed, according to Boyce, it is "probable" that there was once a Perso–Elamite divinity by the name of *Anahiti (as reconstructed from the Greek Anaitis). It is then likely (so Boyce) that it was this divinity that was an analogue of Ishtar, and that it is this divinity with which Aredvi Sura Anahita was conflated.

The link between Anahita and Ishtar is part of the wider theory that Iranian kingship had Mesopotamian roots and that the Persian gods were natural extensions of the Babylonian deities, where Ahuramazda is considered an aspect of Marduk, Mithra for Shamash, and, finally, Anahita was Ishtar. This is supported by how Ishtar "apparently" gave Aredvi Sura Anahita the epithet Banu, 'the Lady', a typically Mesopotamian construct that is not attested as an epithet for a divinity in Iran before the common era. It is completely unknown in the texts of the Avesta, but evident in Sassanid-era middle Persian inscriptions (see Evidence of a cult, below) and in a middle Persian Zend translation of Yasna 68.13. Also in Zoroastrian texts from the post-conquest epoch (651 CE onwards), the divinity is referred to as 'Anahid the Lady', 'Ardwisur the Lady' and 'Ardwisur the Lady of the waters'.

Because the divinity is unattested in any old Western Iranian language, establishing characteristics prior to the introduction of Zoroastrianism in Western Iran (c. 5th century BCE) is very much in the realm of speculation. Boyce concludes that "the Achaemenids' devotion to this goddess evidently survived their conversion to Zoroastrianism, and they appear to have used royal influence to have her adopted into the Zoroastrian pantheon." According to an alternate theory, Anahita was perhaps "a daeva of the early and pure Zoroastrian faith, incorporated into the Zoroastrian religion and its revised canon" during the reign of "Artaxerxes I, the Constantine of that faith."