The Church of England (C of E) is the established Christian church in England and the Crown Dependencies. It was the initial church of the Anglican tradition. The Church traces its history to the Christian hierarchy recorded as existing in the Roman province of Britain by the 3rd century and to the 6th-century Gregorian mission to Kent led by Augustine of Canterbury. Its members are called Anglicans.

In 1534, the Church of England renounced the authority of the Papacy under the direction of King Henry VIII, beginning the English Reformation. The guiding theologian that shaped Anglican doctrine was the Reformer Thomas Cranmer, who developed the Church of England's liturgical text, the Book of Common Prayer. Papal authority was briefly restored under Mary I, before her successor Elizabeth I renewed the breach. The Elizabethan Settlement (implemented 1559–1563) concluded the English Reformation, charting a course for the English church to describe itself as a via media between two branches of Protestantism—Lutheranism and Calvinism—and later, a denomination that is both Reformed and Catholic.

In the earlier phase of the English Reformation there were both Catholic and Protestant martyrs. This continued into the later phases, which saw the Penal Laws punish Catholics and nonconforming Protestants. Various factions continued to challenge the leadership and doctrine of the church into the 17th century, which under Charles I veered towards a more Catholic interpretation of the Elizabethan Settlement, especially under Archbishop Laud. Following the victory of the Roundheads in the English Civil War, the Puritan faction dominated and the Book of Common Prayer and episcopacy were abolished. These would be restored under the Stuart Restoration in 1660.

Since the English Reformation, the Church of England has used the English language in the liturgy. As a broad church, the Church of England contains several doctrinal strands: the main traditions are known as Anglo-Catholic, high church, central church, and low church, the last producing a growing evangelical wing that includes Reformed Anglicanism, with a smaller number of Arminian Anglicans. Tensions between theological conservatives and liberals find expression in debates over the ordination of women and same-sex marriage. The British monarch (currently Charles III) is the supreme governor, and the archbishop of Canterbury (vacant since 7 January 2025, after the resignation of Justin Welby) is the most senior cleric. The governing structure of the Church is based on dioceses, each presided over by a bishop. Within each diocese are local parishes. The General Synod of the Church of England is the legislative body for the church and comprises bishops, other clergy and laity. Its measures must be approved by the Parliament of the United Kingdom.

There is evidence for Christianity in Roman Britain as early as the 3rd century. After the fall of the Roman Empire, England was conquered by the Anglo-Saxons, who were pagans, and the Celtic church was confined to Cornwall and Wales. In 597, Pope Gregory I sent missionaries to England to Christianise the Anglo-Saxons. This mission was led by Augustine, who became the first archbishop of Canterbury. The Church of England considers 597 the start of its formal history.

In Northumbria, Celtic missionaries competed with their Roman counterparts. The Celtic and Roman churches disagreed over the date of Easter, baptismal customs, and the style of tonsure worn by monks. King Oswiu of Northumbria summoned the Synod of Whitby in 664. The king decided Northumbria would follow the Roman tradition because Saint Peter and his successors, the bishops of Rome, hold the keys of the kingdom of heaven.

By the late Middle Ages, Catholicism was an essential part of English life and culture. The 9,000 parishes covering all of England were overseen by a hierarchy of deaneries, archdeaconries, dioceses led by bishops, and ultimately the pope who presided over the Catholic Church from Rome. Catholicism taught that the contrite person could cooperate with God towards their salvation by performing good works (see synergism). God's grace was given through the seven sacraments. In the Mass, a priest consecrated bread and wine to become the body and blood of Christ through transubstantiation. The church taught that, in the name of the congregation, the priest offered to God the same sacrifice of Christ on the cross that provided atonement for the sins of humanity. The Mass was also an offering of prayer by which the living could help souls in purgatory. While penance removed the guilt attached to sin, Catholicism taught that a penalty still remained. It was believed that most people would end their lives with these penalties unsatisfied and would have to spend time in purgatory. Time in purgatory could be lessened through indulgences and prayers for the dead, which were made possible by the communion of saints.

In 1527, Henry VIII was desperate for a male heir and asked Pope Clement VII to annul his marriage to Catherine of Aragon. When the pope refused, Henry used Parliament to assert royal authority over the English church. In 1533, Parliament passed the Act in Restraint of Appeals, barring legal cases from being appealed outside England. This allowed the Archbishop of Canterbury to annul the marriage without reference to Rome. In November 1534, the Act of Supremacy formally abolished papal authority and declared Henry Supreme Head of the Church of England.