This chapter explores the groundbreaking work of political women who have chosen international and transnational terrains as their sites for activism, advocacy, and governance. There is a technical distinction between international and transnational activism, although the terms are often used interchangeably. The chapter deals with an international focus and examines how women diplomats worked within the United Nations (UN) to secure international agreements to recognize and promote women's rights. It examines the complex international politics that structured the Cold War era and the challenges they posed to efforts to promote women's rights. The chapter traces how transnational women activists challenged male-dominant governments' claims to represent women or women's interests at the UN World Conferences on Women and in the process created new political spaces for women—vibrant global nongovernmental forums. It discusses transnational women activists' efforts to address some of the world's most intractable issues—poverty, dispossession, and war—by reconceptualizing peace and security.