The Douglas A-26 Invader (designated B-26 between 1948 and 1965) is an American twin-engined light bomber and ground attack aircraft. Built by Douglas Aircraft Company during World War II, the Invader also saw service during several major Cold War conflicts. A limited number of highly modified United States Air Force aircraft served in Southeast Asia until 1969. It was a fast aircraft capable of carrying a large bomb load. A range of guns could be fitted to produce a formidable ground-attack aircraft.

A redesignation of the type from A-26 to B-26 led to confusion with the Martin B-26 Marauder, which first flew in November 1940, some 20 months before the Douglas design's maiden flight. 

The early A-26 versions were built in two configurations:

-The A-26B 'B' gun-nose version housed six (and later, eight) .50 caliber machine guns, officially the "all-purpose nose", later known as the "six-gun nose" or "eight-gun nose".

-The A-26C's "glass" "Bombardier nose", contained a Norden bombsight for medium-altitude precision bombing. The A-26C nose section included two fixed M-2 guns, but those were eliminated after underwing gun packs or internal guns in the wings proved effective during colder weather.

With the establishment of the United States Air Force (USAF) as an independent service in 1947, the Strategic Air Command operated the again redesignated B-26 as an RB-26 reconnaissance aircraft in service 1949 to 1950. U.S. Air Forces in Europe continued operating the B-26 until 1957. Tactical Air Command operated the aircraft as both a B-26 and later designated back to A-26; the final variant was designated B-26K until 1966, then it again became the A-26A. This final version continued in service through the late 1960s with active-duty special-operations TAC units, and through 1972 with TAC-gained special-operations units of the Air National Guard.[citation needed]

The U.S. Navy obtained Invaders from the USAF to use these aircraft in their utility squadrons (VU) for target towing and general utility until superseded by the DC-130A variant of the C-130 Hercules. The Navy designation was JD-1 and JD-1D until 1962, then the JD-1 was redesignated UB-26J. The JD-1D was redesignated DB-26J.[citation needed] The CIA also used the type for covert operations.