Western Christianity is one of two sub-divisions of Christianity (Eastern Christianity being the other). Western Christianity is composed of the Latin Church and Western Protestantism, together with their offshoots such as the Old Catholic Church, Independent Catholicism and Restorationism.

The large majority of the world's 2.3 billion Christians are Western Christians (about 2 billion – 1.2 billion Latin Catholic and 800 million Protestant). The original and still major component, the Latin Church, developed under the bishop of Rome. Out of the Latin Church emerged a wide variety of independent Protestant denominations, including Lutheranism and Anglicanism, starting from the Protestant Reformation in the 16th century, as did Independent Catholicism in the 19th century. Thus, the term "Western Christianity" does not describe a single communion or religious denomination, but is applied to distinguish all these denominations collectively from Eastern Christianity.

The establishment of the distinct Latin Church, a particular church sui iuris of the Catholic Church, coincided with the consolidation of the Holy See in Rome, which claimed primacy since Antiquity. The Latin Church is distinct from the Eastern Catholic Churches, also in full communion with the Pope in Rome, and from the Eastern Orthodox Church and Oriental Orthodox Churches, which are not in communion with Rome. These other churches are part of Eastern Christianity. The terms "Western" and "Eastern" in this regard originated with geographical divisions mirroring the cultural divide between the Hellenistic east and Latin West, and the political divide between the Western and Eastern Roman empires. During the Middle Ages adherents of the Latin Church, irrespective of ethnicity, commonly referred to themselves as "Latins" to distinguish themselves from Eastern Christians.

Western Christianity has played a prominent role in the shaping of Western civilization. With the expansion of European colonialism from the Early Modern era, the Latin Church, in time along with its Protestant secessions, spread throughout the Americas, much of the Philippines, Southern Africa, pockets of West Africa, and throughout Australia, and New Zealand. Thus, when used for historical periods after the 16th century, the term "Western Christianity" does not refer to a particular geographical area, but is rather used as a collective term for all these.

Today, the geographical distinction between Western and Eastern Christianity is not nearly as absolute as in Antiquity or the Middle Ages, due to the spread of Christian missionaries, migrations, and globalisation. As such, the adjectives "Western Christianity" and "Eastern Christianity" are typically used to refer to historical origins and differences in theology and liturgy, rather than present geographical locations.

While the Latin Church maintains the use of the Latin liturgical rites, Protestant denominations and Independent Catholicism use a wide variety of liturgical practices.