Siemowit VI of Płock, was a Polish prince member of the House of Piast from the Masovian branch. He was a Duke of Płock, Rawa Mazowiecka, Belz, Płońsk, Zawkrze and Wizna during 1455-1461/62 jointly with his brother, since 1459 ruler over Gostynin.
- Born
- January 2, 1446, January 11, 1446
- Died
- January 1, 1462, January 10, 1462
