Patriarch Cosmas may refer to:
Cosmas I of Alexandria, Greek Patriarch of Alexandria in 727–768 Cosmas I of Constantinople, Ecumenical Patriarch in 1075–1081 Cosmas II of Constantinople, Ecumenical Patriarch in 1146–1147 Cosmas II of Alexandria, Greek Patriarch of Alexandria in 1723–1736 Cosmas III of Constantinople, Ecumenical Patriarch in 1714–1716 Cosmas III of Alexandria, Greek Patriarch of Alexandria in 1737–1746