International treaties have had an important impact on national policies affecting women throughout the world. This is true despite women's marginalized status in most national political systems and the treaties' lack of specific formal sanctions. Using the case of the Convention for the Elimination of All Forms of Discrimination Against Women, the Japanese Equal Employment Opportunity Law, and lawsuits brought by Japanese women against the Sumitomo corporations, we develop an explanation of how international treaties can effect change, even for groups with little economic or political power. First, international treaties provide normative resources that allow local activists to describe their actions in terms of moral imperatives rather than selfish interests. Secondly, international treaties provide structural resources to activists, such as periodic reporting requirements that provide opportunities to embarrass slow-moving governments.