The House of Ostrogski (Polish: Ostrogscy; Lithuanian: Ostrogiškiai; Ukrainian: Острозькі, romanized: Ostroz'ki) was one of the more prominent families in the Kingdom of Poland, the Grand Duchy of Lithuania and in the Polish–Lithuanian Commonwealth.

His son, Prince Feodor Danilovich Ostrogski, was a supporter of King Jagiello, who in 1386 confirmed him in possession of the Ostroh Castle and appointed governor of Volhynia in 1387.

[6] In addition to Ostrog Feodor Danilovich Ostrogski became owner of Korets, Zaslav (Izyaslav, in present Khmelnytskyi Oblast, Ukraine), and other towns.

For several generations the Ostrogskis supported the religion of their forefathers, by opening schools, printing books in Ruthenian language with Cyrillic such as "Ostrog Bible" (written by Ivan Fedorov) and making a generous charitable contributions to the construction of the Orthodox churches in the region.

The last male member of the family was Janusz Ostrogski (d. 1620); the last female was Anna Alojza Ostrogska (1600–54), married to Grand Hetman Jan Karol Chodkiewicz.