Melkite (/ˈmɛlkaɪt/) or Melchite churches are various Eastern Christian churches of the Byzantine Rite, and their members. The name comes from the Central Semitic root m-l-k 'royal', referring to the loyalty to the Byzantine emperor, and became a denominational designation for Christians who accepted imperial religious policies, notably the Council of Chalcedon (451).

Originally, during the Early Middle Ages, Melkites used both Koine Greek and Aramaic (Classical Syriac & Syro-Palestinian) language in their religious life, and initially employed the Antiochian rite in their liturgy, but later (10th–11th century) accepted the Constantinopolitan rite, and incorporated Arabic in parts of their liturgical practices.

In modern times, there are two denominations called Melkite: Orthodox Melkites, the Greek Orthodox Christians of the Near East, and Catholic Melkites, members of the Melkite Catholic Church. Melkites can be of various ethnic origins, and Melkite can be the denominational component of ethnoreligious classifications.

Melkites view themselves as the first Christian community, dating the Melkite Church back to the time of the Apostles. Accordingly, notably to Vatican historiographers and the Ecumenical Patriarchate of Constantinople, this first community is said to have been a mixed one made up of individuals who were Greek, Copts, Roman, Aramean (Syriac), Arabs and Jewish. Secular historians like Edward Gibbon and Ernest Renan held similar views regarding the emergence of the Melkite community.

The emergence of Christological controversies in the first half of the 5th century gave rise to divisions among Eastern Christians in various regions of the Near East. Official state support, provided by the Byzantine imperial government to adherents of Chalcedonian Christianity (451), provided the base for a specific use of Aramaic terms that designated those who were loyal to the empire, not just in regard to their political loyalty, but also in relation to their acceptance of imperial religious policies. Throughout the Near East, all Christians who accepted state-backed Chalcedonian Christianity, became known as Melkites, a term derived from the Hebrew word melekh (similar to Aramaic malkā or malkō, meaning "ruler", "king" or "emperor"), thus designating those who are loyal to the empire and its officially imposed religious policies.

The very term (Melkites) designated all loyalists, regardless of their ethnicity (Greeks, Copts, Hellenized Jews, Arameans (Syriacs), Arabs,...), thus including not only Greek-speaking Chalcedonians, but also those among Aramaic-speaking and Arabic-speaking Christians and Judeo-Christians who were followers of Chalcedonian Christianity. All pro-Chalcedonian Christians throughout Byzantine Syria, Byzantine Phoenicia, Byzantine Palestine and Byzantine Egypt thus became commonly known as Melkites. Since Melkite communities were dominated by Greek episcopate, position of Aramaic-speaking and Arabic-speaking Melkites within the wider Melkite community was somewhat secondary to that of Greek Melkites. That led to the gradual decline of Syriac-Aramaic traditions. Classical Syriac was originally the liturgical language of the Syriac Melkites in Antioch and parts of Syria, while some other Aramaic-speaking Melkites, predominantly of Jewish descent, used the Syro-Palestinian dialect in Palestine and Transjordan instead. The Syriac Melkites changed their church's West Syriac Rite to that of Constantinople in the 9th-11th centuries, requiring new translations of all their Classical Syriac liturgical books. The decline of Syriac-Aramaic traditions among Melkites was enhanced (since the 7th century) by gradual Arabization, that also affected Greek-speaking Melkite communities, since under the Islamic rule Arabic became the main language of public life and administration.

Internal divisions that emerged after the Council of Chalcedon (451) in the eastern patriarchates of Alexandria, Antioch, and Jerusalem, gradually led to the creation of distinctive pro-Chalcedonian (Melkite) and non-Chalcedonian branches, that by the beginning of the 6th century evolved into separate hierarchical structures.

Chalcedonian (Melkite) patriarchates of Alexandria, Antioch, and Jerusalem remained in communion with the Ecumenical Patriarchate of Constantinople. On the other side, among miaphysite non-Chalcedonians, parallel patriarchates emerged in Alexandria (miaphysite Coptic Church) and Antioch (miaphysite Syriac Church).