The Singitic Gulf (Greek: Σιγγιτικός Κόλπος, romanized: Singitikos Kolpos), also known as the Mount Athos Gulf or the Holy Mountain Gulf (Greek: Κόλπος Αγίου Όρους, romanized: Kolpos Agiou Oros) is a gulf of the Thracian Sea, part of the northern Aegean Sea, in Chalkidiki, Greece. It is bounded by Sithonia in the west, and Mount Athos in the east. The island of Ammouliani sits in the northeastern portion of the gulf along Mount Athos. Many of the monasteries of Mount Athos lie along the shore of the Singitic Gulf.