Gregory I
Gregory I may refer to:
- Gregory the Illuminator, Catholicos of the Armenian Apostolic Church in 288–325
- Gregory of Nazianzus, Patriarch Gregory I of Constantinople, in office 379–381
- Pope Gregory I, in office 590–604
- Gregory I of Naples, r. 740–755
- Gregory I, List of Patriarchs of the Bulgarian [Orthodox Church|Patriarch of Bulgaria] c. 940 – c. 944
- Gregory I, Count of Tusculum, r. in 954–1012
- Patriarch Gregory I of Alexandria, Greek Orthodox patriarch, in office 1354–1366
- Maputeoa, Gregorio I Maputeoa, King of Mangareva, r. c. 1830–1857