Which amendment, ratified in 1920, prohibited denying U.S. voting rights on the basis of sex?

The Nineteenth Amendment, ratified in 1920, prohibited denying U.S. voting rights on the basis of sex.

Congress approved the amendment on June 4, 1919, and Tennessee became the thirty-sixth state to ratify it on August 18, 1920. Secretary of State Bainbridge Colby certified the amendment on August 26, which is why August 26 is observed in the United States as Women’s Equality Day.

The amendment resulted from decades of organizing by suffragists, including Susan B. Anthony, Elizabeth Cady Stanton, Ida B. Wells, Alice Paul, and many others. The national campaign included conventions, petitions, marches, lobbying, civil disobedience, and state-level voting reforms.

The amendment’s language barred voting discrimination based on sex, but it did not eliminate every barrier to voting. Many women of color, especially in the South, still faced literacy tests, poll taxes, intimidation, and discriminatory administration. The Voting Rights Act of 1965 addressed many such practices.