A private sector nonprofit organization which works independently from any form of government. Some NGOs working in international development are accredited by the United Nations or its agencies.

The term NGO is typically only applied to organizations that pursue wider social aims with political aspects, but are not openly political organizations. The number of NGOs in the United States is estimated at 1.5 million.

NGOs are organized by both their orientation and level of cooperation. Levels of orientation are: Charitable Orientation, Service Orientation, Participatory Orientation, Empowering Orientation. Levels of cooperation are: Community-based Organizations, Citywide Organizations, National NGOs, International NGOs.