Girl Scouts of the United States of America (GSUSA), commonly referred to as simply Girl Scouts, is a youth organization for girls in the United States and American girls living abroad. Founded by Juliette Gordon Low in 1912, it was organized after Low met Robert Baden-Powell, the founder of Scouting, in 1911. Upon returning to Savannah, Georgia, she telephoned a distant cousin, saying, "I've got something for the girls of Savannah, and all of America, and all the world, and we're going to start it tonight!"Girl Scouts prepares girls to empower themselves and promotes compassion, courage, confidence, character, leadership, entrepreneurship, and active citizenship through activities involving camping, community service, learning first aid, and earning badges by acquiring practical skills. Girl Scouts' achievements are recognized with various special awards, including the Girl Scout Gold, Silver, and Bronze Awards.

Girl Scout membership is organized according to grade, with activities designed for each level. GSUSA is a member of the World Association of Girl Guides and Girl Scouts (WAGGGS) and accepts girls of all backgrounds.

A 1994 Chronicle of Philanthropy poll showed Girl Scouts ranked by the public as the eighth "most popular charity/non-profit in America" among more than 100 charities. It describes itself as "the world's preeminent organization dedicated solely to girls."

Girl Guides (known as Girl Scouts in the United States and some other countries) is a movement found worldwide, which was originally and still largely designed for girls and women only. The movement began in 1909 because girls demanded to take part in the then grassroots Boy Scout Movement.In different places around the world, the movement developed in diverse ways. In some places, girls joined or attempted to join Scouting organizations. In other places, all girl groups were started independently, and as time went on, some of these all girl groups started to open up to boys, while others' started to merge with the boys' organizations.

In other cases, mixed groups were formed, which sometimes later disbanded. In the same way, the name Girl Guide or Girl Scout has been used by groups at different times and in different places, with some groups changing from one to another.

The World Association of Girl Guides and Girl Scouts (WAGGGS) was formed in 1928 and has member organisations in 145 countries. There are now more than 10 million members worldwide. WAGGGS celebrated the centenary of the international Girl Guiding and Girl Scouting Movement over three years, from 2010 to 2012.