The U.S. constitutional amendment that granted women the right to vote is the 19th Amendment, ratified in 1920. This monumental change in American history marked a significant stride toward gender equality in political participation. The 19th Amendment prohibited any U.S. citizen from being denied the right to vote based on sex. Its ratification followed decades of activism by suffragists who fought tirelessly to secure voting rights for women, ultimately expanding democratic participation and altering the landscape of American politics.