Harmonia (/hɑːrˈmoʊniə/; Ancient Greek: Ἁρμονία), in ancient Greek religion, is the immortal goddess of harmony and concord. Her Roman counterpart is Concordia, and her Greek opposite is Eris, whose Roman counterpart is Discordia. Her siblings are Eros/Cupid, Phlegyas, Adrestia, and the twins Phobos and Deimos. Her parents are the Goddess of Love, Aphrodite, and the God of War, Ares.
According to one account, she is the daughter of Ares and Aphrodite. By another account, Harmonia was from Samothrace and was the daughter of Zeus and Electra, her brother Iasion being the founder of the mystic rites celebrated on the island. Finally, Harmonia is rationalized as closely allied to Aphrodite Pandemos, the love that unites all people, the personification of order and civic unity, corresponding to the Roman goddess Concordia.
Almost always, Harmonia is the wife of Cadmus. With Cadmus, she was the mother of Ino, Polydorus, Autonoë, Agave, and Semele. Their youngest son was Illyrius.