A Joint Task Force is a "joint" (multi-service) ad hoc military formation. The task force concept originated with the United States Navy in the 1920s and 1930s.

There are two ways in which a U.S. or U.S.-allied task force may be assigned a number. The first is the originally naval scheme promulgated and governed by the Military Command, Control, Communications, and Computers Executive Board (MC4EB), chaired by the Joint Staff J6. Task force numbers allocated under this scheme form the majority of the listings below.

The second is a by-product of the U.S. Army's procedure for forming task-organised forces for combat, differing from strictly doctrinal assigned table of organization and equipment organizations. A battalion, company or brigade commander has very wide latitude in selecting a task force name, though often the name of the commander is used (e.g. Task Force Faith; Task Force Smith was named for the commander of the 1st Battalion, 21st Infantry Regiment). This has often resulted in derivations from the originator unit's numerical designation being used. For example, when a special operations aviation unit was being formed in the late 1970s, the original unit drew heavily on personnel from the 158th Aviation.