In Irish mythology, Flidas or Flidais (modern spelling: Fliodhas, Fliodhais) is a female member of the Tuatha Dé Danann, known by the epithet Foltchaín ("beautiful hair"). She is believed to have been a goddess of animals, woodlands and fertility, somewhat akin to the Greek Artemis and Roman Diana. "As goddess of wild beasts [...] she rode in a chariot drawn by deer" while "as goddess of the domestic herds" she had a magical cow of plenty.
Flidais is a central figure in the Táin Bó Flidhais ("The Driving off of Flidais's Cattle"), an Ulster Cycle work, where she is the lover of Fergus mac Róich and the owner of a magical herd of cattle. The story, set in Erris, County Mayo tells how Fergus carried her and her cattle away from her husband, Ailill Finn. During the Táin Bó Cúailnge (Cattle Raid of Cooley) she slept in the tent of Ailill mac Máta, king of Connacht, and every seven days her herd supplied milk for the entire army. In Táin Bó Flidhais she has a favoured white cow known as "The Maol" which can feed 300 men from one night's milking. Another Ulster Cycle tale says that it took seven women to satisfy Fergus, unless he could have Flidais. Her affair with Fergus is the subject of oral tradition in County Mayo.