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
See also Constantius III