The Baptists form one of the largest Protestant denominations, with worldwide membership of nearly 35 million. The following distinguish the Baptists from other Protestant communions: (1) Their insistence on baptism of adult believers only; (2) Their concern for freedom of speech and conscience and for freedom from interference by any civil or ecclesiastical authority; (3) The primacy they seek to give to Scripture in matters of faith, doctrine, and morals. (4) The authority they give to the congregation in church affairs.

Forerunners to the Baptist tradition were the Anabaptist congregations, settled in Holland in the early 17th century with groups of Puritan Independents, or Congregationalists that fled from England to Holland. Baptism for adults only was accepted at this time. Returning to England, this group formed the first Baptist congregation in 1611. Shortly thereafter, Roger Williams (1639) formed the first Baptist congregation in Providence, RI. The Baptists grew rapidly in the United States. The democratic, informal, Scripture centered, relatively untheological mode of Baptist service was ideal for any unsettled, rural, or frontier situation. Thus the South, the Midwest, and the Far West were heavily populated, more than were the Northeast or the Middle Atlantic, by Baptists, a pattern that remains true to this day.

On the other hand, because of their emphasis on freedom of conscience and personal beliefs, the importance of Christian life and works, rather than on ritual, their distaste for creeds, dogmas, and ecclesiastical authority, Baptists have also been leaders in theological and social liberalism. Many Baptist seminaries and churches are known for their liberal theology, style of worship, and social attitudes. Baptists were consistently important leaders in establishing the ecumenical movement of the early 20th century. In the controversies that have dominated 20th century American religion, the modernist-fundamentalist, the social gospel-individualist, and the ecumenical-exclusivist controversies, Baptists have appeared in leading roles on both sides.