Anglicanism, also known as Episcopalianism in some countries, is a Western Christian tradition which developed from the practices, liturgy, and identity of the Church of England following the English Reformation, in the context of the Protestant Reformation in Europe. It is one of the largest branches of Christianity, with around 110 million adherents within the Anglican Communion, and more than 400,000 outside of the Anglican Communion, worldwide as of 2025.

Adherents of Anglicanism are called Anglicans; they are also called Episcopalians in some countries. Most are members of national or regional ecclesiastical provinces of the international Anglican Communion, one of the largest Christian bodies in the world, and the world's third-largest Christian communion. The provinces within the Anglican Communion have historically been in full communion with the See of Canterbury and thus with the archbishop of Canterbury, whom the communion refers to as its primus inter pares (Latin, 'first among equals'). The archbishop calls the decennial Lambeth Conference, chairs the meeting of primates, and is the president of the Anglican Consultative Council. Some churches that are not part of the Anglican Communion or recognised by it also call themselves Anglican, including those that are within the Continuing Anglican movement and Anglican realignment.

Anglicans base their Christian faith on the Bible, traditions of the apostolic church, apostolic succession ("historic episcopate"), and the writings of the Church Fathers, as well as historically, the Thirty-nine Articles of Religion and The Books of Homilies.

Anglicanism forms a branch of Western Christianity, having definitively declared its independence from the Holy See at the time of the Elizabethan Religious Settlement. Many of the Anglican formularies of the mid-16th century correspond closely to those of historical Protestantism. In the first half of the 17th century, the Church of England and the associated Church of Ireland were presented by some Anglican divines as comprising a distinct Christian tradition, with theologies, structures, and forms of worship representing a different kind of middle way, or via media, originally between Lutheranism and Calvinism, and later between Protestantism and Catholicism – a perspective that came to be highly influential in later theories of Anglican identity and expressed in the description of Anglicanism as "catholic and reformed". The degree of distinction between Protestant and Catholic tendencies within Anglicanism is routinely a matter of debate both within specific Anglican churches and the Anglican Communion. The Book of Common Prayer is unique to Anglicanism, the collection of services in one prayer book used for centuries. The book is acknowledged as a principal tie that binds the Anglican Communion as a liturgical tradition.

After the American Revolution, Anglican congregations in the United States and British North America (which would later form the basis for the modern country of Canada) were each reconstituted into autonomous churches with their own bishops and self-governing structures; these were known as the Protestant Episcopal Church in the United States and the Church of England in the Dominion of Canada. Through the expansion of the British Empire and the activity of Christian missions, this model was adopted as the model for many newly formed churches, especially in Africa, Australasia, and the Asia-Pacific. In the 19th century, the term Anglicanism was coined to describe the common religious tradition of these churches and also that of the Scottish Episcopal Church, which, though originating earlier within the Church of Scotland, had come to be recognised as sharing this common identity. By the 21st century, the global centre of Anglicanism had shifted to the Global South, particularly sub-Saharan Africa, with 63,497,000 baptised Anglicans in Africa and 23,322,000 baptised Anglicans in Europe in 2020.

The word Anglican originates in Anglicana ecclesia libera sit, a phrase from Magna Carta dated 15 June 1215, meaning 'the English Church shall be free'. Adherents of Anglicanism are called Anglicans. As an adjective, Anglican is used to describe the people, institutions, churches, liturgical traditions, and theological concepts developed by the Church of England.

As a noun, an Anglican is a church member in the Anglican Communion. The word is also used by followers of separated groups that have left the communion or have been founded separately from it. The word originally referred only to the teachings and rites of Christians throughout the world in communion with the see of Canterbury but has come to sometimes be extended to any church following those traditions or rites rather than actual membership in the Anglican Communion.

Although the term Anglican is found referring to the Church of England as far back as the 16th century, its use did not become general until the latter half of the 19th century. In British parliamentary legislation referring to the English Established Church, there is no need for a description; it is simply the Church of England, though the word Protestant is used in many legal acts specifying the succession to the Crown and qualifications for office. When the Union with Ireland Act created the United Church of England and Ireland, it is specified that it shall be one "Protestant Episcopal Church", thereby distinguishing its form of church government from the Presbyterian polity that prevails in the Church of Scotland.