This document defines and categorizes non-governmental organizations (NGOs). It begins by explaining that NGOs are citizen-based associations that operate independently of governments to deliver resources or serve social purposes. NGOs are then defined by the World Bank and Department of Public Information. The document goes on to categorize NGOs based on their orientation (such as charitable, service, or empowering), level of operation (community, city, national, or international), and type (including environmental, quasi-autonomous, or networks). It concludes by distinguishing operational NGOs, which design and implement projects, from advocacy NGOs, which promote specific causes.