Euphrosyne of Opole

Euphrosyne of Opole (1228/30–1292) was a Piast duchess, the youngest daughter of Duke Casimir I of Opole. In 1257 she married her kinsman Casimir I of Kuyavia, bearing him four children, including Władysław I the Elbow-high, the future king who reunited Poland.

After Casimir's death in 1267 she ruled Kuyavia as regent until 1275, amid disputes with the Teutonic Order. That year she married Mestwin II, Duke of Pomerania; the childless marriage ended in divorce, and she died at Brześć Kujawski in 1292.