The National Audubon Society (Audubon; ) is an American non-profit environmental organization dedicated to conservation of birds and their habitats. Located in the United States and incorporated in 1905, Audubon is one of the oldest of such organizations in the world. There are completely independent Audubon Societies in the United States, which were founded several years earlier such as the Massachusetts Audubon Society and Connecticut Audubon Society.

The society has nearly 500 local chapters, each of which is an independent 501(c)(3) non-profit organization voluntarily affiliated with the National Audubon Society. They often organize birdwatching field trips and conservation-related activities. It also coordinates the Christmas Bird Count held each December in the U.S., a model of citizen science, in partnership with Cornell Lab of Ornithology, and the Great Backyard Bird Count each February. Together with Cornell, Audubon created eBird, an online database for bird observation. The National Audubon Society also has many global partners to help birds that migrate beyond the U.S.'s borders, including BirdLife International based in Great Britain, Bird Studies Canada, American Bird Conservancy, and many partners in Latin America and in the Caribbean. Audubon's International Alliances Program (IAP) brings together people throughout the Western Hemisphere to work together to implement conservation solutions at Important Birds Areas (IBAs).