Efthalia "Thaleia" Koutroumanidou (Greek: Ευθάληαα "Θάλεια" Κουτρουμανίδου; born 7 October 1982 in Volos) is a Greek Olympic beach volleyballer at the 2008 Summer Olympics and the 2004 Athens Olympics. She is partnered with Maria Tsiartsiani.[1]