The United States Agency for International Development (USAID) is an independent agency of the U.S. federal government that is primarily responsible for administering civilian foreign aid and development assistance. With a budget of over $27 billion, USAID is one of the largest official aid agencies in the world and accounts for more than half of all U.S. foreign assistance—the highest in the world in absolute dollar terms.

Congress passed the Foreign Assistance Act on September 4, 1961, which reorganized U.S. foreign assistance programs and mandated the creation of an agency to administer economic aid. USAID was subsequently established by the executive order of President John F. Kennedy, who sought to unite several existing foreign assistance organizations and programs under one agency. USAID became the first U.S. foreign assistance organization whose primary focus was long-term socioeconomic development.

USAID's programs are authorized by Congress in the Foreign Assistance Act, which Congress supplements through directions in annual funding appropriation acts and other legislation. As an official component of U.S. foreign policy, USAID operates subject to the guidance of the President, Secretary of State, and the National Security Council. USAID has missions in over 100 countries, primarily in Africa, Asia, Latin America, the Middle East, and Eastern Europe.

USAID's decentralized network of resident field missions is drawn on to manage U.S. Government (USG) programs in low-income countries for a range of purposes.

• Disaster relief
• Poverty relief
• Technical cooperation on global issues, including the environment
• U.S. bilateral interests
• Socioeconomic development