This dissertation explains how the politics of visibility affect relations among states and the political power of marginalized people within them. I show that the key to understanding processes of social change lies in a closer examination of the ways in which-and the degree to which-marginalized groups make governments and societies see and interact with their ideas. Specifically, I explore the politics of lesbian, gay, bisexual, and transgender (LGBT) visibility. For a group that many obse rvers have referred to as "an invisible minority," the newfound presence and influence of LGBT people in many different nation states offers fresh opportunities for the study of socio-political change and the diffusion of norms. Despite similar international pressures, why are the trajectories of socio-legal recognition for marginalized groups so different across states? This question is not answered by conventional explanations of diffusion and social change focusing on differences in international pressures, the fit between domestic and international norms, modernization, or low implementation costs. Instead, specific transnational and international channels and domestic interest groups can make visible political issues that were hidden, and it is that visibility that creates the political resonance of international norms in domestic politics, and can lead to their gradual internalization. A state's openness to international organizations and information flows has demonstrable effects on norm diffusion. It affects the ability of new ideas to enter domestic discourse. Furthermore, the degree to which domestic actors are embedded in transnational advocacy networks illuminates the issue and shapes the speed and direction of diffusion. Visibility has engendered the interactions between movements and states that empower people-mobilizing actors to demand change, influencing the spread of new legal standards, and weaving new ideas into the fabrics of societies. It is this process of "coming out" that leads to the socio-political recognition of rights that alters the situation for such groups. Ultimately, the politics of visibility is located at the intersection of international relations and social movement politics.