Euphrosyne of Masovia also known as Eufrozja (1292–1328/1329) was Duchess of Oświęcim by her marriage. Euphrosyne was the daughter of Boleslaus II of Masovia, Prince of Plock and his second wife Kunigunde, daughter of Ottokar II of Bohemia. The genesis of her name is unknown. This is the first and the last time that princess of Masovian lineage of Piast was named Eufrozyna. Modern Polish historians usually named her Eufrozyna, but in sources she was mentioned mostly as Eufrazja. Euphrosyne was buried in the Dominican monastery in Krakow. Euphrosyne and Władysław had two or three children: