U.S. government agency of volunteers, created by the Peace Corps Act of 1961. (From 1971 to 1982 it was a subagency of an independent agency called ACTION.) It was initiated by President John F. Kennedy (Kennedy, John F.), and its first director was Kennedy's brother-in-law R. Sargent Shriver (Shriver, Sargent).

The purpose of the Peace Corps is to assist other countries in their development efforts by providing skilled workers in the fields of education, agriculture, health, trade, technology, and community development. Peace Corps volunteers are assigned to specific projects on the basis of their skills, education, and experience. Once abroad, the volunteer is expected to function for two years as a good neighbour in the host country, to speak its language, and to live on a level comparable to that of the volunteer's counterparts there.

The Peace Corps grew from 900 volunteers serving 16 countries in 1961 to a peak of 15,556 volunteers in 52 countries in 1966. By 1989 the budget had reduced the number of volunteers to 5,100, but some increases occurred thereafter, the number of countries served having risen to about 90. The organization's global reach extended in the early 1990s to include eastern European countries such as Hungary and Poland in 1990 and extended to the former Soviet Union in 1992, adding China in 1993 and South Africa in 1997. By the early 21st century, 136 countries had hosted more than 170,000 Peace Corps volunteers through four decades of service.

Overseas volunteer services akin to the Peace Corps are maintained by other countries, while similar humanitarian work is sponsored by nongovernmental organizations such as Doctors Without Borders.