Social movement theories provide a framework for explaining the post-1990 rise in China's citizen-organized environmental nongovernmental organizations (ENGOs), which consisted of at least 128 organizations as of 2004. We use a political process model, which is based on favorable political opportunities, cognitive liberation, and indigenous organizational strength, to explain the sharp growth in citizen organized ENGOs. In addition, we employ a world society perspective to help clarify why the political environment in China became favorable for ENGO growth, and how international ENGO practices were diffused within China. Our analysis shows that the relatively high status of ENGO founders together with their personal and professional networks also played important roles in ENGO growth.