Gregory VI (Greek: Γρηγόριος ΣΤ΄), baptismal name Georgios Fourtouniadis (Greek: Γεώργιος Φουρτουνιάδης; March 1, 1798 - June 8, 1881) was Ecumenical Patriarch in the periods 1835-1840 and 1867-1871.