Janusz III of Masovia was a Polish prince member of the House of Piast in the Masovian branch. He was a Duke of Czersk, Warsaw, Liw, Zakroczym and Nur from 1503 to 1524 jointly with his brother, and sole ruler from 1524 to 1526 as the last male member of the Masovian Piasts.
- Occupation
- aristocrat
- Citizenship
- Kingdom of Poland
- Born
- 1502
- Died
- March 10, 1526
