In United States doctrine, unconventional warfare (abbreviated UW) is the term for guerrilla warfare that is conducted or supported by units in the United States Special Operations Command. Guerrilla warfare is one aspect of the broader term insurgency. The American definition of UW is:


UW was the first mission assigned to United States Army Special Forces when they were formed in 1952; they now have additional missions, including foreign internal defense (FID). In the United States, "special forces" refers specifically to the United States Army Special Forces (SF), as opposed to the usage in most other countries, where "special forces" refers to the range of unit types that the U.S. calls "special operations forces" controlled by the United States Special Operations Command (USSOCOM). SF units are tasked with seven primary missions:

• unconventional warfare (United States Department of Defense doctrine) (UW)
• foreign internal defense (FID)
• special reconnaissance (SR)
• direct action (DA)
• counter-terrorism (CT)
• counter-proliferation (CP)
• psychological operations (United States) (PsyOps)
• information operations (IO)