Constance of Penthièvre (Breton: Konstanza Penture, or Konstanza Breizh) (12 June 1161 – 5 September 1201) is hereditary Duchess of Brittany between 1171 and 1196.

Constance is the only child of Conan IV, Duke of Brittany and Earl of Richmond, by his wife Margaret of Huntingdon, a sister of King Malcolm IV and William I of Scotland.