The Duchy of Palatinate-Zweibrücken was a duchy of the Holy Roman Empire with full voting rights to the Reichstag. Its capital was Zweibrücken. The reigning house, a branch of the Wittelsbach dynasty, was also the Royal House of Sweden from 1654 to 1720.

A duchy, also called a dukedom, is a medieval country, territory, fief, or domain ruled by a duke or duchess, a ruler hierarchically second to the king or queen in Western European tradition.