Friends of the Earth International (FoEI) is an international network of grassroots environmental organizations in 73 countries. About half of the member groups call themselves "Friends of the Earth" in their own languages; the others use other names. The organization was founded in 1969 in San Francisco by David Brower, Donald Aitken and Gary Soucie after Brower's split with the Sierra Club because of the latter's positive approach to nuclear energy. The founding donation of $500,000 was provided by Robert Orville Anderson, the owner of Atlantic Richfield oil company. It became an international network of organizations in 1971 with a meeting of representatives from four countries: U.S., Sweden, the UK and France.

David Ross Brower was a prominent environmentalist and the founder of many environmental organizations, including the John Muir Institute for Environmental Studies (1997), Friends of the Earth (1969), Earth Island Institute (1982), North Cascades Conservation Council, and Fate of the Earth Conferences. From 1952 to 1969, he served as the first Executive Director of the Sierra Club, and served on its board three times: from 1941–1953; 1983–1988; and 1995–2000 as a petition candidate enlisted by reform-activists known as the John Muir Sierrans. As a younger man, he was a prominent mountaineer.