Which amendment to the United States Constitution prohibited denying the vote on account of sex?

The Nineteenth Amendment prohibited denying United States citizens the right to vote on account of sex.

Congress proposed the amendment in 1919, and Tennessee became the thirty-sixth state to ratify it on August 18, 1920, providing the approval needed for adoption. Secretary of State Bainbridge Colby certified it on August 26, 1920.

The amendment was the result of a long suffrage movement involving activists such as Susan B. Anthony, Elizabeth Cady Stanton, Sojourner Truth, Ida B. Wells, and Alice Paul. Its wording barred federal and state governments from using sex as a legal reason to deny voting rights.

Ratification did not instantly make voting equally accessible to every woman. Many Black women continued to face discriminatory barriers, including poll taxes, literacy tests, intimidation, and restrictive registration practices. The Voting Rights Act of 1965 later strengthened federal protection against racial discrimination in voting.