Barbēlō (Greek: Βαρβηλώ) refers to the first emanation of God in several forms of Gnostic cosmogony. Barbēlō is often depicted as a supreme female principle, the single passive antecedent of creation in its manifold. This figure is also variously referred to as 'Mother-Father' (hinting at her apparent androgyny), 'The Triple Androgynous Name', or 'Eternal Aeon'. So prominent was her place amongst some Gnostics that some schools were designated as Barbeliotae, Barbēlō worshippers or Barbēlō gnostics.

In the Apocryphon of John, a tractate in the Nag Hammadi Library containing the most extensive recounting of the Sethian Gnostic creation myth, the Barbēlō is described as "the first power, the glory, Barbēlō, the perfect glory in the aeons, the glory of the revelation". All subsequent acts of creation within the divine sphere (save, crucially, that of the lowest aeon Sophia) occurs through her coaction with God. The text describes her thus:

This is the first thought, his image; she became the womb of everything, for it is she who is prior to them all, the Mother-Father (Anthropos), the holy Spirit, the thrice-male, the thrice-powerful, the thrice-named androgynous one, and the eternal aeon among the invisible ones, and the first to come forth.

Barbēlō is found in other Nag Hammadi writings:

In Zostrianos, Barbelo has three sublevels or subaeons that represent three distinct phases:

In The Gospel of Judas, Jesus challenges the Twelve Apostles to stand up and face him if they are "[strong enough] among humans to bring out the perfect Humanity. Only Judas is able to meet Jesus' challenge, standing before him and saying "I know who you are and where you've come from. You've come from the immortal realm of Barbelo, and I'm not worthy to utter the name of the one who's sent you."p. 23 Jesus responds by commanding him to "Step away from the others and I shall tell you the mysteries of the kingdom."p. 23 The scene is modeled after the Confession of Peter in the synoptic Gospels, where Jesus asks the Disciples who people say he is, and then who the disciples themselves think he is; Peter correctly states that he is the Messiah, and Jesus responds by giving him favored status among the Apostles (Matthew 16:13–23). There is a similar scene in the Gospel of Thomas, which climaxes with Thomas saying "Teacher, my mouth is utterly unable to say what you are like."p. 23

In the Pistis Sophia Barbēlō is named often, but her place is not clearly defined. She is one of the gods (p. 359), "a great power of the Invisible God" (373), joined with Him and the three "Thrice-powerful deities" (379), the mother of Pistis Sophia (361) and of other beings (49); from her Jesus received His "garment of light" or heavenly body (13, 128; cf. 116, 121); the earth apparently is the "matter of Barbēlō" (128) or the "place of Barbēlō" (373).

She is obscurely described by Irenaeus as "a never-aging aeon in a virginal spirit", to whom, according to certain "Gnostici", the Innominable Father wished to manifest Himself, and who, when four successive beings, whose names express thought and life, had come forth from Him, was quickened with joy at the sight, and herself gave birth to three (or four) other like beings.