The Defense Advanced Research Projects Agency (DARPA) is an agency of the U.S. Department of Defense responsible for the development of emerging technologies for use by the military.

DARPA was created in 1958 as the Advanced Research Projects Agency (ARPA) by President Dwight D. Eisenhower. Its purpose was to formulate and execute research and development projects to expand the frontiers of technology and science, with the aim to reach beyond immediate military requirements. The administration was responding to the Soviet launching of Sputnik 1 in 1957, and DARPA's mission was to ensure U.S. military technology would be more sophisticated than that of the nation's potential enemies.

The name of the organization changed several times from its founding name ARPA: DARPA (March 1972), ARPA (February 1993), and DARPA (March 1996).

DARPA is independent from other military research and development and reports directly to senior Department of Defense management. DARPA has ca. 240 personnel (13 in management, close to 140 technical) directly managing a $3 billion budget.