In Greek mythology, Peitho (Ancient Greek: Πειθώ, romanized: Peithō, lit. 'Persuasion' or 'winning eloquence') is the personification of persuasion. She is a goddess of charming speech. She is typically presented as an important companion of Aphrodite. Her opposite is Bia, the personification of force. As a personification, she was sometimes imagined as a goddess and sometimes an abstract power with her name used both as a common and proper noun. There is evidence that Peitho was referred to as a goddess before she was referred to as an abstract concept, which is rare for a personification. Peitho represents both sexual and political persuasion. She is associated with the art of rhetoric.

Peitho's ancestry is unclear, as various authors provide different identities for her parents. Hesiod in Theogony identifies Peitho as the daughter of the Titans Tethys and Oceanus, which would make her an Oceanid and the sister of notable goddesses such as Dione, Doris, and Metis. According to the lyric poet Sappho, she was the daughter of Aphrodite. Aeschylus identifies her as the daughter of Aphrodite in Suppliant Women (Hiketides), but also describes her as the child of Ate in Agamemnon. Nonnus in his Dionysiaca describes the Charites (Graces), an ensemble of goddesses of grace and charm, as including Peitho, Pasithea, and Aglaia, and all of them are identified as daughters of Dionysus. The Hellenistic era elegiac poet Hermesianax also refers to Peitho as one of the Charites. Alcman describes her as the daughter of Prometheia and the sister of Tyche and Eunomia.

Nonnus identifies Peitho as the wife of Hermes, the messenger of the gods. However, commentary on Euripides' Orestes notes that Peitho is the wife of Phoroneus, the primordial King of Argos, and the mother of Aegialeus, Apis, Europs and Niobe. An alternative Argive tradition describes her instead as the wife of Argos, Phoroneus's grandson. The Byzantine encyclopedic text, Suda, states that the mother of Iynx was either Peitho or Ekho.

Peitho plays a limited role in mythology, mainly appearing with or as a companion of Aphrodite.

A degraded fragment by Sappho may identify Peitho as an attendant of Aphrodite, although other possibilities are Hebe, Iris, or even Hekate. Pindar characterizes Peitho, either as the abstract concept of persuasion or the goddess, as a wise one that holds the "secret key to holy love", associating her with Aphrodite. She is also described as the nurse of the baby Erotes, who are Aphrodite's children. A fragment by Ibycus describes Aphrodite and Peitho, who is described as tendered eyed (aganoblepharos), nursing Euryalus among rose blossoms.

Nonnus gives her a role within the marriage of Kadmos and Harmonia, as she appears to Kadmos in the form of a mortal slave and covers Kadmos in a mist to lead him unseen through Samothrace to the palace of Electra, Harmonia's adoptive mother. Peitho often appears on a 5th century epinetron by the Eretria Painter depicting Harmonia’s bridal preparations with Aphrodite, Eros, Persephone (Kore), Hebe, and Himeros as in attendance. In art, she was also depicted at the weddings for Dionysus and Ariadne, Alkestis and Admetos, Thetis and Peleus, and at the union of Aphrodite and Adonis. A hydria attributed to the Meidias Painter shows Peitho fleeing from the scene of the abduction of the Leukippidai by the Dioskuri, indicating either that she persuaded the women into eloping or that she does not condone the marriage by Athenian standards.

When Zeus ordered the creation of the first woman, Pandora, Peitho and the Charites placed golden necklaces around her neck, and the Horae (Seasons) crowned Pandora's head with spring flowers. Extravagant jewelry, particularly necklaces, were viewed with suspicion in Ancient Greek literature, as they were typically seen as a way for women to seduce men, making the necklace a way to enhance Pandora’s sexual attractiveness and persuasive abilities.

In art, Peitho is often represented with Aphrodite during the abduction of Helen, symbolizing the forces of persuasion and love at work during the scene. Her presence at the event may be interpreted as either Paris needing persuasion to claim Helen as a prize for choosing Aphrodite, or Helen needing to be persuaded to accompany him to Troy, as Helen's level of agency became a popular topic of discussion in the 5th century. Peitho's presence brings the question of whether mortals have the ability to resist her power or whether they are bound to her persuasive abilities.