Palatinate-Zweibrücken-Birkenfeld was a state of the Holy Roman Empire based around Birkenfeld in modern Rhineland-Palatinate, Germany.
Palatinate-Zweibrücken-Birkenfeld was created in 1569 in the partition of Palatinate-Zweibrücken after the death of Wolfgang for his youngest son Charles I. After Charles' death in 1600 his state was partitioned into itself and Palatinate-Birkenfeld-Bischweiler by his sons, with George William succeeding him in Birkenfeld. In 1635 the state was invaded and devastated during the Thirty Years' War, and in the same year decimated by an outbreak of the Plague. George William died in 1669 and was succeeded by his son Charles II Otto. Two years later he died, and with him the male line of the branch, so the state passed to Christian II of Palatinate-Birkenfeld-Bischweiler. Christian II died in 1717 and was succeeded by his son Christian III. In 1731 Christian inherited the Duchy of Zweibrücken and its seat in the Imperial Diet, and renamed his territories to Palatinate-Birkenfeld-Zweibrücken.