From 1865 to 1920, the United States underwent significant constitutional change, forging the legal framework in which race and sex classifications became integral parts of the Constitution and its interpretation. By analyzing congressional debates, Supreme Court decisions, and contemporaneous legal journal articles, this thesis investigates the implications of the Fourteenth and Nineteenth Amendments for women’s jury service rights and obligations. How and why did the federal government legitimize women’s exclusion from juries while simultaneously opposing racial discrimination in jury service selection? This thesis argues that the Fourteenth Amendment, the congressional debate concerning it, and the Court interpretations of it made sex and race antagonistic legal categories, as illustrated in discussions about jury service. In these jury service debates and policies, legislators and jurists relied on notions of gender difference to justify sex discrimination in jury selection as acceptable, benign, and necessary. In addition, the Reconstruction Amendments and their legacy focused the women’s rights movement on attaining suffrage, shaped the scope and language of the Nineteenth Amendment, and limited its effects on women's jury service eligibility.