Odeion (Odeum)
	Odeion of Ancient Agora of Thessaloniki
	Odeion of Gortyn
	Odeion of Patras
	Oil- press and "Cella"of the Church at Asklepeio
	Oil-Press at Agia Paraskevi
	Oil-press at panochori, Lefkas
	Oinoe Tower
	Old building of Faculty of Philosophy, A.U.TH. - former National Preparatory School Idadiye
	Old Cathedral of Serres
	Old Female Boarding School at Gythio
	Old Fortress of Corfu
	Old Gymnasion of Neapolis
	Old Municipal School at Lagkadeika Corinthias
	Old Municipal School at Stimagka (Corinth)
	Old Ottoman School at Hierapetra
	Old Parliament Building
	Old Primary School at Kalochori
	Old primary school at Lithina
	Old School - ex Domestic Sciences School
	Old temple of Athena
	Old Town Hall
	Olympia's Treasuries
	Osman Schah Camii ("Koursoum Camii")
	Osmanie Djami
	Our Lady of the Castle (Panayia tou Kastrou), Medieval Town of Rhodes
	Our Lady (Panayia) Gourlomata
	Our Lady (Panayia) Katholiki
	Our Lady (Panayia) Thermiani