This essay explores women’s antiwar activism in New York, California, and Kansas demonstrating the national breadth and regional diversity of pacifist and peace organizing. The essay identifies some of the individual women who raised their voices and pens against the war and includes some of the antiwar and pacifist organizations women created or joined including the Woman’s Peace Party, the People’s Council, and the Union Against Militarism. It argues that women of the First World War peace movement linked state-sanctioned violence in war with state-sanctioned violence against women, children, and the poor. Women thus contributed to the process by which the peace movement transitioned from defining peace as the absence of war to defining peace as the presence of social, economic, and political justice.