Wild Weasel is a code name given by the United States Air Force (USAF) to any aircraft equipped with anti-radiation missiles and used to suppress enemy air defenses by destroying their radar and surface-to-air missile (SAM) installations. A Wild Weasel pilot baits an enemy into targeting their aircraft with their radars, then traces the radar emissions back to their source, allowing the Weasel or its teammates to precisely target it for destruction.

The USAF developed the Wild Weasel concept in 1965 during the Vietnam War after Soviet SAMs began downing American strike aircraft participating in Operation Rolling Thunder over North Vietnam. The program was headed by General Kenneth Dempster. "The first Wild Weasel success came soon after the first Wild Weasel mission 20 December 1965 when Captains Al Lamb and Jack Donovan took out a site during a Rolling Thunder strike on the railyard at Yen Bai, some 75 mi (120 km) northwest of Hanoi", wrote historian Walter J. Boyne. Wild Weasel tactics and techniques were adopted by other nations and integrated into U.S. efforts to suppress enemy air defenses to establish air supremacy before full-scale conflict.

The missions were known by the operational code "Iron Hand" when first authorized on 12 August 1965, though technically this term referred only to the suppression attack before the main strike. The term "Wild Weasel" derives from Project Wild Weasel, the USAF development program for a dedicated SAM-detection and suppression aircraft. Originally named "Project Ferret", denoting a predatory animal that goes into its prey's den to kill it (hence: "to ferret out"), the name was changed to differentiate it from the code-name "Ferret" that had been used during World War II for radar-countermeasures bombers.

The Wild Weasel concept was proposed in 1965 to counter the increasing North Vietnamese SAM threat. Air Force crews flew the two-seat F model of the F-100 Super Sabre, while the United States Navy primarily relied upon the A-4 Skyhawk. The F-100F Wild Weasel lacked the performance characteristics to survive in a high threat environment. The first Wild Weasel squadron was the 354th Tactical Fighter Squadron based at Takhli Royal Thai Air Base, Thailand. After 45 days of operations against North Vietnamese targets, the 354th had one airplane left and of the 16 aircrew members, four had been killed, two were prisoners of war, three had been wounded and two had quit.

The Wild Weasel II version was the first unsuccessful attempt to use the F-4C Phantom as a Wild Weasel platform. When that effort failed, the Wild Weasel role was then passed to the F-105F in the summer of 1966. The F-105F was converted for the role and was designated Wild Weasel III. The F-105F was equipped with more advanced radar, jamming equipment, and a heavier armament. Anti-radiation missiles were outfitted that could seek out radar emplacements. The F-105F Wild Weasel airframes were eventually modified with improved countermeasures components in a standardized configuration and designated the F-105G. The F-105G was also designated Wild Weasel III; 61 F-105F units were upgraded to F-105G specifications. Although in some documentation the F-105F was referred to as an EF-105F, that designation never existed in the operational flying squadrons.

The F-105 was no longer in production by 1964. With severe combat attrition of the F-105 inventory, the need for a more sophisticated aircraft resulted in the conversion of 36 F-4C Phantom II aircraft, designated F-4C Wild Weasel IV. The F-4C Wild Weasel IV also bore the unofficial designation of EF-4C.

The F-4E, the most advanced Phantom variant with extensive ground-attack capabilities and an internal gun, became the basis for the F-4G Wild Weasel V (also known as the Advanced Wild Weasel). This modification consisted of removing the gun and replacing it with the APR-38(t) Radar Homing and Warning Receiver (later upgraded to the APR-47), and a cockpit upgrade for the back seat to manage the electronic combat environment. A total of 134 F-4G models were converted from F-4Es with the first one flying in 1975. Squadron service began in 1978.

F-4Gs were deployed to three active wings. One was stationed at George AFB, Victorville, California, as part of the Rapid Deployment Force; one wing was assigned to USAFE (US Air Forces in Europe) at Spangdahlem AB, Germany; and the other to PACAF (Pacific Air Forces) at Clark AB, Philippines. F-4Gs from George AFB, Clark AB and Spangdahlem AB saw combat during Operation Desert Storm in 1991, successfully protecting strike packages from enemy air defenses. During this conflict the F-4G saw heavy use, with only a single loss: an aircraft from Spangdahlem AB crashed in Saudi Arabia while returning from a mission, after one of the AGM-88 HARM anti-radiation missiles hang fired which left the aircraft's instruments not displaying the correct altitude information and a significant frame tweak from the damage made the plane hard to control. After an investigation into the loss of the aircraft which occurred during several aborted landing attempts in a sandstorm, it was determined that a fuel cell was punctured by anti-aircraft fire. The pilot and EWO safely ejected after the engines shut down when the aircraft ran out of fuel attempting to land at a forward airstrip.