Circe (; Ancient Greek: Κίρκη, pronounced [kírkɛː]) is an enchantress and a minor goddess in ancient Greek mythology and religion. She is a daughter of the Titan Helios and the Oceanid nymph Perse. Circe was renowned for her vast knowledge of potions and herbs. Through the use of these and a magic wand or staff, she would transform her enemies, or those who offended her, into animals.

The best known of her legends is told in Homer's Odyssey when Odysseus visits her island of Aeaea on the way back from the Trojan War and she changes most of his crew into swine. He manages to persuade her to return them to human shape, lives with her for a year and has sons by her, including Latinus and Telegonus. Her ability to change others into animals is further highlighted by the story of Picus, an Italian king whom she turns into a woodpecker for resisting her advances. Another story tells of her falling in love with the sea-god Glaucus, who prefers the nymph Scylla to her. In revenge, Circe poisoned the water where her rival bathed and turned her into a dreadful monster.

Depictions, even in Classical times, diverged from the detail in Homer's narrative, which was later to be reinterpreted morally as a cautionary story against drunkenness. Early philosophical questions were also raised about whether the change from being a human endowed with reason to being an unreasoning beast might not be preferable after all, and the resulting debate was to have a powerful impact during the Renaissance. Circe was also taken as the archetype of the predatory female. In the eyes of those from a later age, this behaviour made her notorious both as a magician and as a type of sexually free woman. She has been frequently depicted as such in all the arts from the Renaissance down to modern times.

Western paintings established a visual iconography for the figure, but also went for inspiration to other stories concerning Circe that appear in Ovid's Metamorphoses. The episodes of Scylla and Picus added the vice of violent jealousy to her bad qualities and made her a figure of fear as well as of desire.