The United World Federalists was a non-partisan, non-profit organization with members in forty-eight states. This organization was founded in Asheville, North Carolina on February 23, 1947 as the result of a merger of five existing world government groups: Americans United for World Government; World Federalists, U.S.A.; Student Federalists; Georgia World Citizens Committee; and the Massachusetts Committee for World Federation. The organization became World Federalists, USA in the 1960s, before changing its name again in the 1970s to World Federalists Association.

The primary purpose of the organization is: (1) to achieve permanent peace through universal disarmament enforced by law; (2) to release for the satisfaction of human needs the resources that at present must be used in continuous preparation for war; (3) to maintain and promote human freedom, and to mobilize support for free institutions among all peoples; (4) to secure to all peoples the right to develop according to their own customs and traditions. Based entirely in the United States it is one of the largest member organizations of the World Federalist Movement. While the two organizations work closely together on many programs, they are incorporated separately, with separate staffs, headquarters, and governing boards.