Theodosius (from the Greek "Θεοδόσιος", "Giver of God") is a name which might refer to one of several people:
- One of three emperors of ancient Rome and Byzantium:
- Theodosius I (347–395; "Theodosius the Great"), son of Count Theodosius
- Theodosius II (408–450)
- Theodosius III (715–717)
- One of three Pope of the Coptic Orthodox Church
Others by the name are:
- Theodosius of Bithynia or Theodosius of Tripolis (c. 160 BC– c. 100 BC) was a Greek astronomer and mathematician.
- Patriarch Theodosius I of Alexandria (535–567)
- Patriarch Theodosius II of Alexandria (c. 12th century)
- Theodosius of Kiev, 11th century Russian saint.
- Theodosius, Metropolitan of Moscow (1461–1464)
- Metropolitan Theodosius (Lazor), former primate of the Orthodox Church in America (1933– )
