Casimir II of Belz

Casimir II of Belz (pl: Kazimierz II bełski; 1401/03 – 15 September 1442), was a Polish prince member of the House of Piast from the Masovian branch. He was a Duke of Płock, Rawa Mazowiecka, Gostynin, Sochaczew, Belz, Płońsk, Zawkrze and Wizna during 1426–1434 jointly with his brothers, and after the division of the paternal inheritance between him and his brothers in 1434, sole ruler over Belz.

He was the third son of Siemowit IV, Duke of Masovia and Alexandra of Lithuania, daughter of Algirdas.