an agency of Protestant, Anglican, and Eastern Orthodox denominations that was formed in 1950 in the United States by the merger of 12 national interdenominational agencies. The National Council of Churches is the largest ecumenical body in the United States, with a membership of more than 50 million in the early 21st century. Its international counterpart is the World Council of Churches. The National Council's purpose is to provide an organization through which member churches can express their common faith and cooperate with one another on various programs. The council's headquarters are in New York City.

The National Council of Churches has initiated many interchurch activities, including a revision of the English Bible (the New Revised Standard Version, 1989); the publication of religious education, evangelism, and family-life materials; and the promotion of religious and moral values in broadcasting. The council also encourages collaboration with overseas churches in the use of mass media; it fights against illiteracy and enlists local churches to fight against hunger through better agriculture, nutrition, and family planning.

In the 21st century the council's membership was made up of 36 Protestant and Eastern Orthodox churches as full members, with other church bodies, including conservative Protestants and Roman Catholics, participating in its programs.