The American Legion, commonly known as the Legion, is a nonprofit organization of US war veterans headquartered in Indianapolis, Indiana. It is made up of state, U.S. territory, and overseas departments, and these are in turn made up of local posts. The organization was formed on March 15, 1919, in Paris, France, by a thousand officers and men of the American Expeditionary Forces (A. E. F.), and it was chartered on September 16, 1919, by the United States Congress.

The Legion played the leading role in the drafting and passing of the Servicemen's Readjustment Act of 1944, commonly known as the "G.I. Bill". In addition to organizing commemorative events, members provide assistance at Department of Veterans Affairs (VA) hospitals and clinics. It is active in issue-oriented U.S. politics. Its primary political activity is lobbying on behalf of interests of veterans and service members, including support for benefits such as pensions and the Veterans Health Administration. It has also historically promoted Americanism, individual obligation to the community, state, and nation; peace and good will.