Iaia of Cyzicus ("Marcia") was a Roman painter, alive during the time of Marcus Terentius Varro (116-27 BC).
Born in Cyzicus, she was a famous painter and ivory engraver. Most of her paintings are said to be of women. Among pictures ascribed to her was a large panel, in Naples, picture of an old woman and a self-portrait. She was said to have worked faster and painted better than her male competitors, Sopolis and Dionysius, which enabled her to earn more than them. Marcia remained unmarried all her life.