| Honorific-Prefix: | His All Holiness |
| Theodosius II | |
| Patriarch Of: | Ecumenical Patriarch of Constantinople |
| Enthroned: | 22 April 1769 |
| Ended: | 27 November 1773 |
| Diocese: | Constantinople |
| See: | Ecumenical Patriarchate |
| Church: | Church of Constantinople |
| Predecessor: | Meletius II |
| Successor: | Samuel |
| Birth Name: | Christianopoulos (Χριστιανόπουλος) |
| Birth Date: | unknown |
| Birth Place: | Crete |
| Death Date: | after 1776 |
| Death Place: | Istanbul |
| Religion: | Eastern Orthodox Church |
| Occupation: | Ecumenical Patriarch |
Theodosius II (Greek, Modern (1453-);: Θεοδόσιος), lay surname Christianopoulos (Χριστιανόπουλος), served as the Ecumenical Patriarch of Constantinople between 1769 and 1773.
He was born in Crete, where he was father superior. He served as chief of the Church of St. George in Istanbul. Later he was elected bishop of Ierissos and Mount Athos, and in 1767 metropolitan bishop of Thessaloniki. He was elected Patriarch on 11 April 1769, at a time when Christians were persecuted after the withdrawal of the Russian forces following the Orlov Revolt. Many Christians had helped the Russians, following the exhortations of the former Patriarch Seraphim II and other clerics. Theodosius made efforts to save the monasteries of Mount Athos from demolition, he freed prisoners, he supported schools and monasteries and, with cooperation with the Patriarch of Jerusalem Sophronius V, he managed to keep the Holy Land under the jurisdiction of the Eastern Orthodox Church. Lastly, he tried to give a conciliatory solution[1] to the issue of the Kollyvades of Mount Athos.
He was forced to resign on 16 November 1773, following the machinations of the Metropolitan of Prussa, Meletius. He retired to the Kamariotissa Monastery in Heybeliada. In 1776, having completely lost his sight, he returned to Istanbul, where he resided until his death.