Evangelicalism (), also called evangelical Christianity or evangelical Protestantism, is a worldwide interdenominational movement within Protestant Christianity that affirms the centrality of being "born again", in which an individual experiences personal conversion; the authority of the Bible as God's revelation to humanity (biblical inerrancy); and spreading the Christian message. The word evangelical comes from the Greek (euangelion) word for "good news".

Its origins are usually traced to 1738, with various theological streams contributing to its foundation, including Pietism and Radical Pietism, Puritanism, Quakerism, Presbyterianism and Moravianism (in particular its bishop Nicolaus Zinzendorf and his community at Herrnhut). Preeminently, John Wesley and other early Methodists were at the root of sparking this new movement during the First Great Awakening. Today, evangelicals are found across many Protestant branches, as well as in various denominations around the world, not subsumed to a specific branch. Among leaders and major figures of the evangelical Protestant movement were Nicolaus Zinzendorf, George Fox, John Wesley, George Whitefield, Jonathan Edwards, Billy Graham, Bill Bright, Harold Ockenga, Gudina Tumsa, John Stott, Francisco Olazábal, William J. Seymour, Martyn Lloyd-Jones.

The movement has long had a presence in the Anglosphere before spreading further afield in the 19th, 20th and early 21st centuries. The movement gained great momentum during the 18th and 19th centuries with the Great Awakenings in Great Britain and the United States.

In 2016, there were an estimated 619 million evangelicals in the world, meaning that one in four Christians would be classified as evangelical. The United States has the largest proportion of evangelicals in the world. American evangelicals are a quarter of that nation's population and its single largest religious group. As a transdenominational coalition, evangelicals can be found in nearly every Protestant denomination and tradition, particularly within the Reformed (Continental Reformed, Presbyterian, Congregational), Plymouth Brethren, Baptist, Methodist (Wesleyan–Arminian), Lutheran, Moravian, Free Church, Mennonite, Quaker, Pentecostal/charismatic and non-denominational churches.