The North American A-5 Vigilante is an American carrier-based supersonic bomber designed and built by North American Aviation (NAA) for the United States Navy. Before the 1962 unification of Navy and Air Force designations, it was designated A3J.

Development of the A-5 had started in 1954 as a private venture by NAA, who sought to produce a capable supersonic long-distance bomber as a successor to the abortive North American XA2J Super Savage. It was a large and complex aircraft that incorporated several innovative features, such as being the first bomber to feature a digital computer, while its ability to attain speeds of up to Mach 2 while carrying a nuclear strike payload was also relatively ambitious for the era. The US Navy saw the value of such a bomber, leading to a contract for its full development and production being issued to the firm on 29 August 1956. The type performed its first flight just over two years later, on 31 August 1958.

The Vigilante was introduced by the US Navy during June 1961; it succeeded the Douglas A-3 Skywarrior as the Navy's primary nuclear strike aircraft, but its service in this capacity was relatively brief due to the deemphasizing of manned bombers in American nuclear strategy. A far larger quantity of the RA-5C tactical strike reconnaissance variant were also procured by the service, which saw extensive service during the Vietnam War. It also established several world records in both long-distance speed and altitude categories. During the mid-1970s, the withdrawal of the type commenced after a relatively short service life, largely due to the aircraft being expensive and complex to operate, as well as being a victim of post-Vietnam military cutbacks.

The late 1940s and early 1950s were marked by a series of fast-paced advancements in the field of aviation. The aircraft manufacturer North American Aviation (NAA) was one of a large number of companies that sought to harness these recent innovations in developing a new generation of aircraft. During early 1954, the company embarked on a private study into a conceptual carrier-based, long-range, all-weather strike bomber, that would be capable of supersonic speeds while carrying a sizable payload. This aircraft was envisioned as a successor to the abortive North American XA2J Super Savage. Much of this early work was undertaken by NAA's recently acquired Columbus division, overseen by chief of preliminary design Frank G. Compton.

During the mid-1950s, the notion of a nuclear-armed aircraft capable of speeds of up to Mach 2 was considered to be quite ambitious, and only more so for that same aircraft to be operable under the unavoidable constraints imposed by aircraft carrier operations. In terms of its basic configuration, the conceptual aircraft featured twin-engines and high-mounted wing, as did the XA2J, but differed substantially by being highly swept and adopting jet propulsion. According to aviation authors Bill Gunston and Peter Gilchrist, NAA's design incorporated numerous advanced technology features, such as being the first supersonic bomber to be designed with a slim forward fuselage, as well as being the first with fully-variable wedge-type side air intakes. The company's preliminary design studies had been typically centered around a twin vertical fin/rudder arrangement, but this was substituted for a single large all-moving vertical fin as design definition proceeded.

This proposal, which was referred to the North American General Purpose Attack Weapon (NAGPAW) concept, was promptly evaluated by the United States Navy. The service produced numerous challenging demands, including the somewhat contradictory necessity of both a high speed of Mach 2 and the ability to take off from an aircraft carrier at maximum weight with no head-wind, also known as wind-over-the-deck, to assist the take-off. Compton's team were able to reconcile these performance requirements into the design. Following these changes, US Navy officials voiced their approval of the design and advocated for its procurement. During July 1955, an initial design contract, which included the production of a mockup, was issued to NAA. During September 1956, a follow-on contract for the production of a pair of flight-worthy prototypes, was awarded to the firm.

On 31 August 1958, one of these prototypes performed the type's maiden flight from Columbus, Ohio. By this point, the role envisioned for the aircraft within the US Navy had shifted somewhat. According to Gunston and Gilchrist, officials had viewed the aircraft through the lens of the Korean War and placed a high value on performing low-level conventionally-armed attack missions, but had subsequently shifted towards viewing the in-development bomber as a successor to the Douglas A-3 Skywarrior in the strategic nuclear attack role instead. Thus, the design team implemented a somewhat unorthodox bomb bay as to accommodate the stowage of a nuclear weapon, which was also designed to accommodate both fuel tanks and reconnaissance payloads.

During the late 1950s and early 1960s, NAA worked on an improved bomber model, designated A-5B. This took advantage of the zero-wind requirement's elimination to considerably increase the aircraft's maximum weight, the fuselage being redesigned with a hump back to accommodate additional fuel. The wings were also redesigned with enlarged trailing-edge flaps and fully-blown flaps; these changes, when carrying four external drop tanks, roughly doubled the bomber's range. Development was halted after only six A-5Bs had been completed due to a shift in the US Navy's strategic focus that placed less value on manned bombers.