The League of Women Voters is an American political organization founded in 1920 by Carrie Chapman Catt during the last meeting of the National American Woman Suffrage Association approximately six months before the Nineteenth Amendment to the United States Constitution gave U.S. women the right to vote. It began as a "mighty political experiment" aimed to help newly-enfranchised women exercise their responsibilities as voters. Originally, only women could join the league; but in 1973 the charter was modified to include men. The league is a grassroots organization with chapters in all 50 states plus the District of Columbia, Puerto Rico, and the U.S. Virgin Islands. The league has approximately 150,000 members (as of 2006).

The league is nonpartisan, meaning it does not endorse or oppose political candidates or parties at any level of government. The league does support or oppose many political issues after studying them and coming to a consensus on a position. The league works to increase understanding of major public policy issues, and to influence public policy through education and advocacy, as well as through political lobbying of Congress.

The league is organized into two complementary halves: Voters Service and Citizen Education; and Program and Action.