John Casimir, Count Palatine of Zweibrücken-Kleeburg was the son of John I, Count Palatine of Zweibrücken and his wife, Duchess Magdalene of Jülich-Cleves-Berg. He was married to Catherine of Sweden and was the founder of a branch of Wittelsbach Counts Palatine often called the Swedish line, because it gave rise to three subsequent kings of Sweden, but more commonly known as the Kleeburg line.

Zweibrücken is a town in Rhineland-Palatinate, Germany, on the Schwarzbach river.