• Syriac Orthodox
• Assyrian Church of the East, the Assyrian Orthodox Church.
• Eastern Christianity, referring collectively to the Eastern Christian churches and their religious traditions
• Eastern Orthodox Church, the Church descended from the Imperial Church of the Byzantine Empire
• Oriental Orthodoxy, the communion of Eastern Christian Churches that recognize only the first three ecumenical councils, and reject the dogmatic definitions of the Council of Chalcedon
• Orthodox Christianity

Orthodox in Judaism may refer to:

• Modern Orthodox Judaism or Neo-Orthodox Judaism
• Orthodox Judaism, a set of Judaic traditions characterized by traditional interpretation of Jewish law
• Ultra-Orthodox Judaism Haredi or Chareidi Judaism.

Secular meanings of Orthodox include:

• Orthodox stance, in boxing, the designation for the normal stance for a right-handed boxer or Mixed Martial Arts combatant.
• Orthodox seed, a seed which may be preserved via drying or freezing.

See also

• Orthodoxy
• Lutheran Orthodoxy