Nongovernmental organizations (NGOs) engage in a host of activities to influence world political affairs. They lobby states, pressure economic actors and alter cultural frames to shape widespread thought and behavior. Most scholars of international relations ignore the cultural dimension of NGO work either because it seemingly lacks clear political significance or because alterations in cultural life are difficult to gauge. In this article I demonstrate that, while less direct and obvious, NGO cultural challenges may have, ironically, more political relevance than conventional forms of activism and engagement. Additionally, I show that, notwithstanding formidable methodological challenges, there are ways to measure shifts in broad ideational frameworks—even across borders—and scholars can adopt these in productive ways. I develop both these points through a study of environmental NGOs. The article's findings, however, can be generalized beyond environmental organizations to all types of NGOs.