List of Christian denominations by number of members

This is a list of Christian denominations by number of members. It is inevitably partial and generally based on claims by the denominations themselves. The numbers should therefore be considered approximate and the article an ongoing work-in-progress.

The list includes the six main taxonomically divided groups which are the: Church of the East, Oriental Orthodoxy, Eastern Orthodoxy, Catholicism, Protestantism, and Restorationism. This list additionally includes individual denominations such as the Eastern Catholic Churches, independent Catholic denominations, offshoots of both Eastern and Oriental Orthodoxy, as well as Protestant and Restorationist denominations with at least 200,000 members.

Christianity is the largest religious group in the world, with an estimated 2.3 to 2.6 billion adherents in 2020.

Christian denominational families

The various denominations of Christianity fall into several large families, shaped both by culture and history.

Christianity arose in the first century AD after Rome had conquered much of the western parts of the fragmented Hellenistic empire created by Alexander the Great. The linguistic and cultural divisions of the first century AD Roman Empire with, broadly speaking, a Latin West and a Greek East, but also with significant areas in North Africa where Coptic was the dominant language, and areas in the Near East where Syriac or Aramaic was the dominant language, were reflected in the early Christian church. The church was called "Catholic" meaning "universal" from very early in the second century, a tacit acknowledgement of the many different cultures it encompassed.