This paper is designed to understand the relationship between states and nongovernmental organizations (NGOs), especially foreign aid policy and the field activities of NGOs. In this study, I argue that NGOs influence states’ foreign aid policy behaviors toward other states directly, functioning as information providers and lobbying groups. By applying theoretical arguments to the field of international development, the influence of NGOs on states’ decisions about foreign aid is analyzed with the case of the United States. A new time-series cross-sectional data set of the activities of US-based NGOs in developing countries is constructed. This study shows that as the number of US-based NGO field operations in developing countries increases, that country is significantly more likely to receive higher amounts of aid from the United States. NGOs that have longer operations in developing countries are also more effective at lobbying the United States to provide more foreign aid.