In Greek mythology, Eros (UK: /ˈɪərɒs, ˈɛrɒs/, US: /ˈɛrɒs, ˈɛroʊs/;[2] Ancient Greek: Ἔρως, romanized: Érōs, lit. 'Desire') is the Greek god of love and sex. His Roman counterpart was Cupid ("desire"). In the earliest account, he is a primordial god, while in later accounts he is described as one of the children of Aphrodite and Ares and, with some of his siblings, was one of the Erotes, a group of winged love gods.

Eros appears in ancient Greek sources under several different guises. In the earliest sources (the cosmogonies, the earliest philosophers, and texts referring to the mystery religions), he is one of the primordial gods involved in the coming into being of the cosmos. In later sources, however, Eros is represented as the son of Aphrodite, whose mischievous interventions in the affairs of gods and mortals cause bonds of love to form, often illicitly. Ultimately, in the later satirical poets, he is represented as a blindfolded child, the precursor to the chubby Renaissance Cupid, whereas in early Greek poetry and art, Eros was depicted as a young adult male who embodies sexual power, and a profound artist.

A cult of Eros existed in pre-classical Greece, but it was much less important than that of Aphrodite. However, in late antiquity, Eros was worshiped by a fertility cult in Thespiae. In Athens, he shared a very popular cult with Aphrodite, and the fourth day of every month was sacred to him (also shared by Herakles, Hermes and Aphrodite).

Eros was one of the Erotes, along with other figures such as Himeros and Pothos, who are sometimes considered patrons of homosexual love between males. Eros is also part of a triad of gods that played roles in homoerotic relationships, along with Heracles and Hermes, who bestowed qualities of beauty (and loyalty), strength, and eloquence, respectively, onto male lovers.

The Thespians celebrated the Erotidia (Ancient Greek: Ἐρωτίδεια) meaning festivals of Eros.