Gwen Teirbron (French: Blanche; Latin: Alba Trimammis or Candida; possibly English: Wite) was a Breton holy woman and wife of Fragan who supposedly lived in the 5th or 6th century.

Her epithet is Welsh for '(of the) three breasts'.

Popular devotion interpreted Gwen's unusual physical and spiritual fecundity by God's gift to her of a third breast.

Gwen is invoked for women's fertility.

She is commemorated on 3 October in the Roman Catholic Church (although this has been transferred from Saint Candidus of Rome), and on 18 July (NS) by the Russian Orthodox Church Abroad in Australia.