Yes in one sense, and no in another. Eastern Orthodox Christians confess the Church as “one, holy, catholic, and apostolic,” using catholic in its ancient sense of whole, complete, or universal. But the Eastern Orthodox Church is not the Roman Catholic Church and does not accept Roman Catholic ecclesial authority as its own.
What “catholic” means in the Creed
The word catholic predates the later division between Eastern Orthodoxy and Roman Catholicism. In the Nicene-Constantinopolitan Creed, Christians confess belief in one holy, catholic, and apostolic Church. Orthodox teaching understands catholicity as the fullness and wholeness of the Church’s faith and life.
This is why an Orthodox Christian can say the Orthodox Church is catholic without saying it is Roman Catholic. Capitalization and context matter in English: “Catholic Church” often means the church in communion with the bishop of Rome, while “catholic” can describe a theological quality of the Church.
Why the Orthodox and Roman Catholic churches are distinct
Eastern Orthodox and Roman Catholic Christians share much of early Christian history, Scripture, ancient creeds, sacramental life, episcopal ministry, and devotion to saints. Over centuries, however, disputes about authority, theology, language, politics, and church discipline contributed to separation between the Christian East and West.
The conventional date 1054 is often used for the Great Schism, but the separation developed gradually rather than in a single moment. Later events, including the Crusades and the sack of Constantinople in 1204, deepened estrangement.
The major issue of papal authority
A central difference concerns the role of the bishop of Rome. Roman Catholic teaching gives the pope a universal primacy with defined authority in the whole Catholic Church. Eastern Orthodoxy recognizes historical primacy associated with Rome in the first millennium but rejects the later Roman Catholic model of universal papal jurisdiction.
Orthodox churches are organized as a communion of self-governing churches united in faith, sacraments, and episcopal order rather than under one universal bishop with Roman Catholic powers.
Are their sacraments and beliefs the same?
They are similar in many areas but not identical. Both traditions have bishops, priests, the Eucharist, baptism, confession, fasting, liturgical calendars, saints, and monastic life. Differences include papal authority, some formulations about the Holy Spirit, developments in doctrine, disciplinary practices, and certain approaches to theology.
It is therefore misleading either to say that Orthodoxy is simply “Catholicism without the pope” or that the two traditions have nothing in common.
A clear way to state the answer
The Eastern Orthodox Church understands itself as catholic in the ancient creedal sense, but it is not part of the Roman Catholic Church. The two are distinct Christian communions that share substantial early heritage while remaining separated.
For more context, see Eastern Orthodoxy and Roman Catholicism.
