The Greek Orthodox Church (Monotonic Greek: Ελληνορθόδοξη Εκκλησία, Polytonic: Ἑλληνορθόδοξη Ἑκκλησία, IPA: [elinorˈθoðoksi ekliˈsia]) is the body of several churches within the larger communion of Eastern Orthodox Christianity sharing a common cultural tradition whose liturgy is also traditionally conducted in Koine Greek, the original language of the New Testament. The church's current territory more or less covers areas in the Eastern Mediterranean that used to be a part of the Byzantine Empire.

The churches where the Greek Orthodox term is applicable are:

Another autocephalous church which can be described as Greek Orthodox is the Orthodox Church of Albania. Led since the collapse of the former Stalinist régime by Archbishop Anastasios, a Greek national, the Church conducts its liturgy in Koine Greek in the areas of Albania populated by the ethnic Greek minority.

Historically, the term Greek Orthodox has also been used to describe all Eastern Orthodox Churches, since "Greek" in "Greek Orthodox" can refer to the Greek heritage of the Byzantine Empire. During eight centuries of Christian history most major intellectual, cultural, and social developments in the Christian church took place within the Empire or in the sphere of its influence, thus most parts of the liturgy, traditions, and practices of the church of Constantinople were adopted by all, and still provide the basic patterns of contemporary Orthodoxy. However, the appellation "Greek" was abandoned by Slavic and other national orthodox churches in connection with their peoples' national awakenings, from as early as the 10th century A.D.

The Greek is a fictional character on the HBO drama The Wire, played by actor Bill Raymond. The Greek is the head of an international criminal organization involved in narcotics and human trafficking. The Greek is a mysterious figure involved in numerous criminal activities. His given name is never mentioned on the show, and though he is known only as "The Greek", he has stated (in the episode Port in a Storm) that he is not actually Greek. A quiet and unassuming man, the Greek prefers to keep a low profile, operating all of his business through his lieutenant Spiros "Vondas" Vondopoulos. His smuggling organization operated from a small diner in Baltimore for years, and while Vondas would conduct business the Greek would listen in quietly at the counter. Nick Sobotka, upon seeing the Greek identify himself, was amazed that the shadowy figure had been in plain sight the entire time.

Despite his calm appearance, the Greek is cunning and ruthless, and only interested in facts that make him more money. Series creator David Simon has said that The Greek is an embodiment of raw unencumbered capitalism. Anyone interfering in this process is eliminated immediately, and he prefers to leave victims headless and handless to hinder identification.

Lycourgos Angelopoulos is the founder and director of the Greek Byzantine Choir. He is also an Archon Protopsaltes (lead cantor) of the Archdiocese of Constantinople.

Lycourgos Angelopoulos is a member of Simon Karas Byzantine chanting school, and in his performance practice and choir training he follows some of Karas' innovations, such as the subtle peculiarities of Byzantine modes interpretation, and the use of "extended" neumatic notation. Angelopoulos also authors several publications dedicated to Byzantine chant in general, and the school of thought inspired by Simon Karas in particular.

James Likoudis is a former lecturer in religious studies.

In 1977 Likoudis translated Casin's St. Thomas Aquinas, Orthodoxy, and Neo-Modernism in the Church from French to English. Likoudis also has authored several books dealing with sex education, the Eastern Orthodox church, liturgical issues following the Second Vatican Council and articles and commentary about prominent Catholics.

Likoudis co-authored The Pope, the Council and the Mass (Christopher Publishing House), a defense of Pope Paul VI's Ordo Missae and the genuine liturgical reforms envisaged by the Second Vatican Council. L'Osservatore Romano noted in 1981: "This book has been sorely needed for well over a decade". The book was republished in 2006.

A convert to the Catholic Church in 1952, Likoudis has since devoted a great deal of his efforts to foster the reunion of the Eastern Orthodox churches with the Catholic Church. Likoudis' book, Ending the Byzantine Greek Schism (2nd revised edition, 1992) deals with the historical and theological issues raised by Eastern Orthodoxy.