Religion was a major factor in nineteenth-century American life that also served to reinforce women’s inferior status to men. In this paper, I examine the role of both atheist feminism and Christian feminism in the late nineteenth-century American women’s rights movement, and argue that atheist feminism had a greater influence on the advancement of women’s rights in the years following the Civil War. Though there were a variety of organized religions in America throughout the nineteenth-century, for the sake of this paper I focus strictly on Christianity, as it was the dominant religion at the time. The atheist feminist perspective cited Christianity as the primary source of female oppression and inequality. Atheist feminists argued that the disbelief in Christianity and its teachings was necessary for women to escape their inferior status imposed upon them by Christian orthodoxy. The opposition to the atheist feminist perspective was Christian feminism. Christian feminists supported the teachings of the Bible, and argued that Christianity promoted women’s equality. Atheist feminism has been largely excluded from the history of the women’s rights movement, and many historians cite Christian feminism as the most significant sect of feminism within the movement. However, many of the most important figures in the women’s rights movement advocated irreligious stances toward women’s rights and the history of the women’s rights movement deserves an analysis of the important, yet often overlooked role of atheist feminism in the late nineteenth-century women’s rights movement. The recognition of religion as a force behind the women’s rights movement has brought with it the need to recognize the contribution of irreligion to the women’s rights movement, particularly the role of atheist feminism.