Constantine III

Constantine III may refer to:


 * Constantine III (Western Roman emperor), self-proclaimed western Roman Emperor 407–411
 * Heraclius Constantine, Byzantine Emperor in 641
 * Constans II, Byzantine emperor 641–668, sometimes referred to under this name
 * Constantine III of Abkhazia, king of Abkhazia in 898/99–916/17
 * Constantine III of Scotland, king of Scotland 995–997
 * Patriarch Constantine III of Constantinople (ruled 1059–1063)
 * Constantine III of Armenia (ruled 1344–1362)
 * Constantine III of Cilicia, Catholicos of the Holy See of Cilicia in 1323–1326
 * Constantine III, Prince of Mukhrani (1696–1756), Georgian prince