Apologetic has been an ongoing activity in the Church since the apostolic times. The eighteenth century witnessed one of the most famous apologists in Christian history: John Wesley. Wesley, a subscribed minister in the Church of England, defended himself against criticism from his fellow churchmen when they charged him with differing from the 'common interpretation' of the Thirty-Nine Articles. This thesis examines critiques of John Wesley and Methodism, and how Wesley dealt with them. It concentrates on the debates between John Wesley and three of his major opponents; namely, Josiah Tucker, Thomas Church, and 'John Smith'.The defensive position in which Wesley found himself in following criticism from fellow clergymen shaped his methodology throughout his ministry when defending Christianity in general and 'Methodism' in particular; consequently, placing apologetic at the centre of his writings. When defending 'Methodism' against those who attacked it as an enthusiastic aberration, this thesis demonstrates that Wesley customarily appealed to the formularies of the Church of England: The Articles, the Homilies and the Common Book of Prayer. To those who attacked his doctrine of salvation by faith alone, Wesley responded by appealing to the formularies, and demonstrated that his interpretation of the formularies was in accordance with the Church Fathers, and with the compilers of the formularies. By excluding good works as conditions of justification and rejecting the charge of 'enthusiasm to the highest degree', Wesley showed that his doctrines, including salvation by faith alone were grounded in Scripture and took reason into account in their elaboration. Despite some hesitations in defining his doctrine of perfection, Wesley showed that he did not teach sinless perfection. When defending his connections with the Moravians, Wesley demonstrated that he rejected some Moravian tenets that did not meet his consent. Wesley contended that 'Methodism' contributed to Church renewal and robust Christian faith in individuals. When dealing with the 'perceptible inspiration' or the 'witness of the Spirit'. Wesley based his arguments on Scripture and his interpretation of the formularies. Wesley insisted that the Holy Spirit inwardly convinces the recipient that their sins are forgiven and that they are a child of God. According to Wesley, the Holy Ghost witnesses to the believer directly. When facing those who believed that miracles had ceased with the apostles, and who argued that God gave the apostles an 'implicit faith' which allowed them to work miracles with the aim of establishing the church at that precise time, and God had withdrawn the gift after the fulfillment of the mission, Wesley rejected any possibility of an 'implicit faith' and insisted that God still worked miracles in the eighteenth century. All the correspondence between Wesley and his first three major opponents in the early life of 'Methodism' is critically examined in this thesis. Wesley's hesitations when building up his doctrines are also highlighted. This thesis instructs us that when facing adversity Wesley in the defence of 'Methodism', frequently adapted his methodology to meet new circumstances.