Which amendment to the U.S. Constitution prohibited denying the vote based on sex?

The Nineteenth Amendment to the U.S. Constitution prohibited denying or abridging the right to vote on account of sex. It was ratified on August 18, 1920, and certified on August 26.

The amendment followed decades of organizing by women’s suffrage activists. The Seneca Falls Convention of 1848 helped launch a national movement, while activists including Susan B. Anthony, Elizabeth Cady Stanton, Ida B. Wells, and Carrie Chapman Catt pursued constitutional and state-level reforms.

Its wording barred sex-based voting discrimination by the United States and the states. It did not create a completely equal voting system, because racial discrimination, citizenship restrictions, and other barriers continued to prevent many women from voting.

The amendment was sometimes called the Susan B. Anthony Amendment, although Anthony died in 1906 and therefore did not see its ratification. The constitutional change marked a major milestone in American political history.