Joannicius III (Greek: Ιωαννίκιος Γ΄ Serbian: Јоаникије III) born Ioannis Karatzas was Archbishop of Peć and Patriarch of the Serbs from 1739 to 1746 and Ecumenical Patriarch of Constantinople from 1761 to 1763. The ordinal number of his title is III both for his office as Patriarch of Pec and of Constantinople.