In Roman mythology, Bona Dea ("the good goddess") was a goddess of fertility, healing, virginity and women. She was a daughter of Faunus and was sometimes called Fauna.

There was a temple to Bona Dea on the Aventine Hill. On December 4, secret rites in honor of her were held in the house of a famous Roman magistrate. It was an entirely female affair; even paintings or drawings of men or male animals were forbidden, along with the words "wine" and "myrtle" because Bona Dea had once been beaten by her father with a myrtle stick after she got drunk.

Her public festival took place on May 1. No men were allowed to participate.

The sick were tended to in the gardens outside her temples, where medicinal herbs were grown by priestesses.

She was associated with the cornucopia, snakes and coins. Her image frequently occurred on ancient Roman coins.