Is Catholicism a Denomination? It Is a Christian Church That Does Not Call Itself One

Catholicism is a form of Christianity, and whether to call it a denomination depends on who is speaking. The Cambridge Dictionary does, naming Roman Catholicism. The Catholic Church does not: it teaches that the one Church of Christ “subsists in” the Catholic Church, and so it speaks of itself as that Church, not as one branch among many.

The Pew Research Center groups denominations into a few broad traditions and calls Catholicism “the world’s largest Christian tradition,” next to the Protestant and Orthodox traditions. The Vatican counted just over 1.422 billion Catholics at the end of 2024.

Who calls Catholicism a denomination?

What is a denomination?

A denomination is a named religious body within a larger religion. The Cambridge Dictionary defines it as “a religious group that has slightly different beliefs from other groups that share the same religion,” and Dictionary.com as “a religious group, usually including many local churches, often larger than a sect.” The Oxford Advanced Learner’s Dictionary gives, first, “a branch of the Christian Church.”

The word itself means a naming. It entered English in the late fourteenth century, through French, from the Latin denominare, “to name.” The Online Etymology Dictionary dates its religious sense to 1716, the adjective denominational to 1838, and denominationalism, a “tendency to divide into sects or denominations,” to 1845.

Two senses of the word need keeping apart. In the descriptive sense of the dictionaries, a named body within Christianity, Catholicism fits. The question Catholics answer differently is theological: whether the Church of Christ is nothing more than the sum of the separated churches, a picture the Catholic Church rejects. Sociologists use the word in a third way, for one type of religious body in church-sect theory; Howard Becker’s scheme of 1932, for instance, was a “cult-sect-denomination-ecclesia model.”

Why doesn’t the Catholic Church call itself a denomination?

Because it teaches that Christ founded one Church, and that this Church continues in the Catholic Church. The Second Vatican Council’s decree on ecumenism, Unitatis Redintegratio (1964), says in its opening lines: “Christ the Lord founded one Church and one Church only.” Many Christian communions, it goes on, “differ in mind and go their different ways, as if Christ Himself were divided.”

The Council’s constitution on the Church, Lumen Gentium, says where that one Church is found. It “subsists in the Catholic Church, which is governed by the successor of Peter and by the Bishops in communion with him, although many elements of sanctification and of truth are found outside of its visible structure” (8). In 2000 the Congregation for the Doctrine of the Faith explained the phrase in Dominus Iesus: the Church of Christ “continues to exist fully only in the Catholic Church” (16). The same document rejects the theological picture in so many words, quoting the Congregation’s declaration Mysterium Ecclesiae of 1973: Catholics are “not permitted to imagine that the Church of Christ is nothing more than a collection — divided, yet in some way one — of Churches and ecclesial communities” (17).

That teaching does not deny that other Christians are Christians. The decree on ecumenism says that those who “believe in Christ and have been truly baptized are in communion with the Catholic Church even though this communion is imperfect,” and that they “have a right to be called Christian” (3). Dominus Iesus draws a line between churches that keep “apostolic succession and a valid Eucharist,” which it calls “true particular Churches,” and ecclesial communities that have not kept them, which it says “are not Churches in the proper sense,” while their baptized members are “incorporated in Christ” (17).

The decree grounds its call for unity in the prayer Jesus offered for his followers before his death, for “them also which shall believe on me through their word” (John 17:20):

“That they all may be one; as thou, Father, art in me, and I in thee, that they also may be one in us: that the world may believe that thou hast sent me.” (John 17:21)

Nor are the churches inside the Catholic Church denominations of it. The Latin Church and the 23 Eastern Catholic churches keep their own rites and law, but the Council describes their members as united “by the same faith, the same sacraments and the same government” (Orientalium Ecclesiarum 2). Are there Catholic denominations? sets out the 24 churches.

How do Protestants and the Orthodox see it?

Each church answers from its own account of what the Church is.

The Westminster Confession of 1646, quoted here in the American revision that the Orthodox Presbyterian Church publishes, teaches that “the catholic or universal church, which is invisible, consists of the whole number of the elect,” and that the visible church “consists of all those throughout the world that profess the true religion.” Within it, “particular churches, which are members thereof, are more or less pure, according as the doctrine of the gospel is taught and embraced.” On that view the universal Church is larger than any single body, and speaking of denominations comes naturally. The Confession also rejects the authority of the pope: “There is no other head of the church but the Lord Jesus Christ. Nor can the pope of Rome, in any sense, be head thereof.”

Anglicans hold that their church belongs to the one Church without being Roman Catholic. When Dominus Iesus appeared in 2000, Archbishop George Carey of Canterbury replied that the Church of England “does not for one moment accept that its orders of ministry and Eucharist are deficient in any way,” and that it “believes itself to be a part of the one, holy, catholic and apostolic church of Christ.”

The Orthodox, like Catholics, do not think of themselves as one denomination among several. The Orthodox Church in America answers a reader who asked about receiving Communion at a Catholic parish that “Orthodox Christians are not permitted to receive Communion in non-Orthodox communities, including the Roman Catholic,” because to do so “would imply a unity that in fact does not yet exist.” The same answer makes a second point: while Catholics call Orthodoxy a “sister church,” “Orthodoxy sees herself as the fullness of the Church, not the ‘other half’ of the Church.” On the Catholic side, Dominus Iesus holds that the Church of Christ “is present and operative also in these Churches,” and places the break with them in the papacy: they lack full communion “since they do not accept the Catholic doctrine of the Primacy” (17).

What the churches still hold in common, and where they part, is the ground covered by Christianity: What Christians Have Believed for 2,000 Years, a free course of eighteen short lessons.

How do researchers count Catholics?

As one of Christianity’s large traditions. Pew’s survey of world Christianity, published in 2011 with figures for 2010, sorted Christians into Catholic, Protestant, Orthodox and other traditions. It found that “About half of all Christians worldwide are Catholic (50%), while more than a third are Protestant (37%),” with the Orthodox at 12 percent. Pew kept the word denomination for the many Protestant bodies, writing that “the doctrines of the various Protestant denominations vary.”

The Church keeps its own count. The Annuario Pontificio for 2026 and the Church’s statistical yearbook put the number of baptized Catholics at the end of 2024 at “just over 1.422 billion, compared with about 1.406 billion in 2023,” about 17.8 percent of the world’s people, as Vatican News reported in March 2026.

Is Catholicism Christianity?

Yes. Some Protestants question whether Catholics are Christians, which is one reason people ask, but in none of the accounts above is Catholicism a separate religion. The Cambridge Dictionary calls it a denomination of the Christian faith, Pew counted its members in 2010 as half of the world’s Christians, the Protestant and Orthodox churches quoted here disagree with it as fellow Christians, and the Catholic Church calls itself the Church of Christ. Catholics profess the Nicene Creed, with its faith in “one Lord, Jesus Christ, the only Son of God.” How Catholics differ from Protestants is set out in Catholic vs Christian.

Related reading

• Roman Catholic vs Catholic: the same Church, with exceptions
• Orthodox vs Catholic: how the two churches differ and why they split
• Anglican vs Catholic: why the Church of England is not Roman Catholic
• How many Christian denominations are there today?
• Largest Christian denominations in the U.S., ranked by membership