NGOs are social and political organizations that work independently from governments. Most NGOs are nonprofits, but not all nonprofits are NGOs. While it’s difficult to count how many NGOs exist today, 2021 data from The U.S. Department of State estimates there are 1.5 million NGOs working in the US alone. Which ones are the biggest? This article describes 15 influential NGOs located in places like the United States, Europe, and South Asia.