| Reign | January 17, 1649- |
| Coronation | January 17, 1649 |
| Royal House | Vasa |
| Predecessor | Ladislaus IV |
| Successor | Michael Korybut Wisniowiecki |
| Date of Birth | March 22, 1609 |
| Place of Birth | Cracow, Poland |
| Date of Death | December 16, 1672 |
| Place of Death | Nevers, France |
John Casimir II Vasa of Poland, or Jan II Kazimierz Waza, (1609-1672), King of the Polish-Lithuanian Commonwealth, and Duke of Opole in Silesia. His parents were Sigismund III of Poland (1566-1632), and Constance of Austria (1588-1631).
His father Sigismund, grandson of Gustav I of Sweden, had succeded his father to the Swedish throne in 1592 only to be deposed from the by his uncle Charles IX of Sweden in 1599. This lead to a long standing feud where the Polish kings of the house of Vasa claimed the Swedish throne. Effects of this were the Swedish War (1600-1629). Poland and Sweden were also on opposite sides in the Thirty Years' War (1618-1648).
In 1648 John II succeeded his half brother and cousin on the Polish throne. In 1660 he would be forced to renounce his claims to the Swedish throne and acknowledge Swedish sovereignty over Livonia and city of Riga. John abdicated on September 16, 1668 and returned to France where he joined the Jesuit order and became an ordinary monk. He died in 1672.
| Preceded by: Ladislaus IV |
King of Poland | Succeeded by: Michael Korybut Wisniowiecki |