Demetrius I

Demetrius I or Demetrios I may refer to:

Demetrius I of Macedon, king of Macedon
Demetrius I of Bactria, Greco-Bactrian king
Demetrius I Soter, ruler of the Hellenistic Seleucid Empire
Pope Demetrius I of Alexandria, ruled in 189–232
Demetrius Zvonimir of Croatia, King of Croatia
Demetrius I of Georgia, Georgian king
Demetrios I Kantakouzenos, Despot of the Morea in 1383
Demetrius I Starshy, Duke of Bryansk
Demetrius I Qadi, Patriarch of the Melkite Greek Catholic Church
Demetrios I of Constantinople, Ecumenical Patriarch of Constantinople in 1972–1991