The Armed Forces Special Weapons Project (AFSWP) was a United States military agency responsible for those aspects of nuclear weapons remaining under military control after the Manhattan Project was succeeded by the Atomic Energy Commission on 1 January 1947. These responsibilities included the maintenance, storage, surveillance, security and handling of nuclear weapons, as well as supporting nuclear testing. The AFSWP was a joint organization, staffed by the United States Army, United States Navy and United States Air Force; its chief was supported by deputies from the other two services. Major General Leslie R. Groves, the former head of the Manhattan Project, was its first chief.

Leslie Richard Groves Jr. was a United States Army Corps of Engineers officer who oversaw the construction of the Pentagon and directed the Manhattan Project, a top secret research project that developed the atomic bomb during World War II.