General characteristics
Crew: 1 pilot
Length: 46 ft 4 in (14.12 m)
Wingspan: 30 ft 4 in (9.25 m)
Height: 11 ft 8 in (3.55 m)
Wing area: 243.4 sq ft (22.61 m²)
Airfoil: supercritical airfoil
Empty weight: 13,968 lb (6,340 kg)
Loaded weight: 22,950 lb (10,410 kg)
Max. takeoff weight: Rolling: 31,000 lb (14,100 kg) Vertical: 20,755 lb (9,415 kg)
Powerplant: 1 × Rolls-Royce F402-RR-408 (Mk 107) vectored-thrust turbofan, 23,500 lbf (105 kN)

Performance
Maximum speed: Mach 0.9 (585 knots, 673 mph, 1,083 km/h)
Range: 1,200 nmi (1,400 mi, 2,200 km)
Combat radius: 300 nmi (350 mi, 556 km)
Ferry range: 1,800 nmi (2,100 mi, 3,300 km)
Rate of climb: 14,700 ft/min (75 m/s)
Wing loading: 94.29 lb/(sq ft) (460.4 kg/m²)

Armament
Guns: 1× General Dynamics GAU-12 Equalizer 25 mm (0.984 in) 5-barreled Rotary cannon mounted under-fuselage in the left pod, with 300 rounds of ammunition in the right pod
Hardpoints: 6× under-wing pylon stations holding up to 9,200 lb (4,200 kg) of payload:
Rockets:
4× LAU-5003 rocket pods (each with 19× CRV7 or APKWS 70 mm rockets)
Missiles:
Air-to-air missiles:
4× AIM-9 Sidewinder or similar-sized infrared-guided missiles
6× AIM-120 AMRAAM (on radar equipped AV-8B Plus variants)
Air-to-surface missiles:
6× AGM-65 Maverick; or
2× AGM-84 Harpoon; or
2× AGM-88 HARM
Bombs:
CBU-100 cluster bombs (CBUs)
Mark 80 series of unguided bombs (including 3 kg [6.6 lb] and 14 kg [31 lb] practice bombs)
Paveway series of laser-guided bombs (LGBs)
Joint Direct Attack Munitions (GBU-38, GBU-32, and GBU-54)
Mark 77 napalm canisters
B61

Others:
up to 4× 300/330/370 US Gallon drop tanks (pylon stations No. 2, 3, 4, & 5 are wet plumbed)
Intrepid Tiger II electronic jammer

Avionics
Raytheon APG-65 radar
AN/AAQ-28V LITENING targeting pod (on radar-equipped AV-8B Plus variants)

In the late 1960s and early 1970s, the first-generation Harriers entered service with the Royal Air Force (RAF) and United States Marine Corps (USMC), but were handicapped in range and payload. In short takeoff and landing configuration, the AV-8A (American designation for the Harrier) carried less than half the 4,000 lb (1,800 kg) payload of the smaller A-4 Skyhawk, over a more limited radius. To address this issue, Hawker Siddeley and McDonnell Douglas began joint development of a more capable version of the Harrier in 1973. Early efforts concentrated on an improved Pegasus engine, designated the Pegasus 15, which was being tested by Bristol Siddeley. Although more powerful, the engine's diameter was too large by 2.75 in (70 mm) to fit into the Harrier easily.

In December 1973, a joint American and British team completed a project document defining an Advanced Harrier powered by the Pegasus 15 engine. The Advanced Harrier was intended to replace the original RAF and USMC Harriers, as well as the USMC's A-4. The aim of the Advanced Harrier was to double the AV-8's payload and range, and was therefore unofficially named AV-16. The British government pulled out of the project in March 1975 owing to decreased defense funding, rising costs, and the RAF's insufficient 60-aircraft requirement. With development costs estimated to be around £180-200 million (1974 British pounds), the United States was unwilling to fund development by itself, and ended the project later that year.

Despite the project's termination, the two companies continued to take different paths toward an enhanced Harrier. Hawker Siddeley focused on a new larger wing that could be retrofitted to existing operational aircraft, while McDonnell Douglas independently pursued a less ambitious, though still expensive, project catering to the needs of the US military. Using knowledge gleaned from the AV-16 effort, though dropping some items-such as the larger Pegasus engine-McDonnell Douglas kept the basic structure and engine for an aircraft tailored for the USMC

The AV-8B Harrier II is a subsonic attack aircraft of metal and composite construction that retains the basic layout of the Hawker Siddeley Harrier, with horizontal stabilizers and shoulder-mounted wings featuring prominent anhedral (downward slope). The aircraft is powered by a single Rolls-Royce Pegasus turbofan engine, which has two intakes and four synchronized vectorable nozzles close to its turbine. Two of these nozzles are located near the forward, cold end of the engine and two are near the rear, hot end of the engine. This arrangement contrasts with most fixed-wing aircraft, which have engine nozzles only at the rear. The Harrier II also has smaller valve-controlled nozzles in the nose, tail, and wingtips to provide control at low airspeeds.

The AV-8B is equipped with one centerline fuselage and six wing hardpoints (compared to four wing hardpoints on the original Harrier), along with two fuselage stations for a 25 mm GAU-12 cannon and ammunition pack. These hardpoints give it the ability to carry a total of 9,200 lb (4,200 kg) of weapons, including air-to-air, air-to-surface, and anti-ship missiles, as well as unguided and guided bombs. The aircraft's internal fuel capacity is 7,500 lb (3,400 kg), up 50 percent compared to its predecessor. Fuel capacity can be carried in hardpoint-compatible external drop tanks, which give the aircraft a maximum ferry range of 2,100 mi (3,300 km) and a combat radius of 300 mi (556 km). The AV-8B can also receive additional fuel via aerial refueling using the probe-and-drogue system. The British Aerospace Harrier II, a variant tailored to the RAF, uses different avionics, and has one additional missile pylon on each wing.

The Harrier II retains the tandem landing gear layout of the first-generation Harriers, although each outrigger landing gear leg was moved from the wingtip to mid-span for a tighter turning radius when taxiing. The engine intakes are larger than those of the first-generation Harrier, and have a revised inlet. On the underside of the fuselage, McDonnell Douglas added lift-improvement devices, which capture the reflected engine exhaust when close to the ground, giving the equivalent of up to 1,200 lb (544 kg) of extra lift.

The technological advances incorporated into the Harrier II, compared with the original Harrier, significantly reduce the workload on the pilot. The supercritical wing, hands-on-throttle-and-stick (HOTAS) control principle, and increased engineered lateral stability make the aircraft fundamentally easier to fly. Ed Harper, general manager for the McDonnell Douglas Harrier II development program, summarized: "The AV-8B looks a lot like the original Harrier and it uses the same operating fundamentals. It just uses them a lot better". A large cathode-ray tube multi-purpose display, taken from the F/A-18, makes up much of the instrument panel in the cockpit. It has a wide range of functions, including radar warning information and weapon delivery checklist. The pilots sit on UPC/Stencel 10B zero-zero ejection seats, meaning that they are able to eject from a stationary aircraft at zero altitude.