USS Missouri (hull number BB-63) is an Iowa-class battleship built for the United States Navy (USN) in the 1940s and is a museum ship. Completed in 1944, she is the last battleship commissioned by the United States. The ship was assigned to the Pacific Theater during World War II, where she participated in the Battles of Iwo Jima and Okinawa and shelled the Japanese home islands. Her quarterdeck was the site where the Japanese Instrument of Surrender was signed, officially ending World War II.

After World War II, Missouri served in various diplomatic, show of force and training missions. In 1950, the ship ran aground during high tide in Chesapeake Bay and after great effort was re-floated several weeks later. She later fought in the Korean War during two tours between 1950 and 1953. Missouri was the first American battleship to arrive in Korean waters and served as the flagship for several admirals. The battleship took part in numerous shore bombardment operations and also served in a screening role for aircraft carriers. Missouri was decommissioned in 1955 and transferred to the reserve fleet (also known as the "Mothball Fleet").

Missouri was reactivated and modernized in 1984 as part of the 600-ship Navy plan. Cruise missile and anti-ship missile launchers were added along with updated electronics. The ship served in the Persian Gulf escorting oil tankers during threats from Iran, often while keeping her fire-control systems trained on land-based Iranian missile launchers. She served in Operation Desert Storm in 1991 including providing fire support.

Missouri was again decommissioned in 1992, but remained on the Naval Vessel Register until her name was struck in 1995. In 1998, she was donated to the USS Missouri Memorial Association and became a museum ship at Pearl Harbor, Hawaii.

The Iowa class of fast battleships was designed in the late 1930s in response to the US Navy's expectations for a future war with the Empire of Japan. The last battleships to be built by the United States, they were also the US Navy's largest and fastest vessels of the type. American officers preferred comparatively slow but heavily armed and armored battleships, but Navy planners determined that such a fleet would have difficulty in bringing the faster Japanese fleet to battle, particularly the Kongō-class battlecruisers and the aircraft carriers of the 1st Air Fleet. Design studies prepared during the development of the earlier North Carolina and South Dakota classes demonstrated the difficulty in resolving the desires of fleet officers with those of the planning staff within the displacement limits imposed by the Washington Naval Treaty system, which had governed capital ship construction since 1923. An escalator clause in the Second London Naval Treaty of 1936 allowed an increase from 35,000 long tons (36,000 t) to 45,000 long tons (46,000 t) in the event that any member nation refused to sign the treaty, which Japan refused to do.

Missouri is 887 feet 3 inches (270.4 m) long overall and is 860 feet (262.1 m) long at the waterline. The ship has a beam of 108 ft 2 in (33 m) and a draft of 37 ft 9 in (11.5 m) at her full combat load of 57,540 long tons (58,460 t). The Iowa-class ships are powered by four General Electric geared steam turbines, each driving one screw propeller using steam provided by eight oil-fired Babcock & Wilcox boilers. Rated at 212,000 shaft horsepower (158,000 kW), the turbines were designed to give a top speed of 32.5 knots (60.2 km/h; 37.4 mph), but were built to handle a 20 percent overload. None of the Iowas ever ran speed trials in deep water, but the Bureau of Ships estimated that they could reach a speed of about 34 knots (63 km/h; 39 mph) from 225,000 shp (168,000 kW) at a light displacement of 51,209 long tons (52,031 t). The ships had a designed cruising range of 15,000 nautical miles (28,000 km; 17,000 mi) at a speed of 15 knots (28 km/h; 17 mph), although the New Jersey's fuel consumption figures during her sea trials suggest that her range was at least 20,150 nmi (37,320 km; 23,190 mi) at that cruising speed. Their designed crew numbered 117 officers and 1,804 enlisted men which had greatly increased by the end of the war in 1945. Missouri's crew at that time numbered 189 officers and 2,978 sailors.

The main battery of the Iowa-class ships consisted of nine 16 in (406 mm)/50 caliber Mark 7 guns in three triple-gun turrets on the centerline, two of which were placed in a superfiring pair forward of the superstructure, with the third aft. Going from bow to stern, the turrets were designated I, II, and III. Their secondary battery consisted of twenty 5 in (127 mm)/38 caliber dual-purpose guns mounted in twin-gun turrets clustered amidships, five turrets on each broadside. Unlike their sister ships Iowa and New Jersey that were the first pair of ships built, Missouri and Wisconsin were completed with an anti-aircraft suite of twenty quadruple mounts for 40 mm (1.6 in) Bofors AA guns, nine mounts on each broadside and one each on the roofs of Turrets II and III. Forty-nine 20-millimeter (0.8 in) Oerlikon light AA auto-cannon in single mounts were distributed almost the length of the ships.

The primary means of controlling the main armament are two Mark 38 directors for the Mark 38 fire-control system mounted at the tops of the fore and aft fire-control towers in the superstructure. These directors were equipped with 25-foot-6-inch-long (7.8 m) rangefinders, although their primary sensor was the Mark 8 fire-control radar mounted on their roofs. A secondary Mark 40 fire-control director was installed inside the armored conning tower at the front of the superstructure that used the Mark 27 fire-control radar positioned on the top of the conning tower. Each turret is fitted with a rangefinder 46 feet (14 m) long and can act as a director for the other turrets. Four Mark 37 gunnery directors, two on the centerline at the ends of the superstructure and one on each broadside, control the five-inch guns. Each director was equipped with a 15-foot (4.6 m) rangefinder and a pair of radars on its roof. These were a Mark 12 fire-control system and a Mark 22 height-finder radar. Each 40 mm mount was remotely controlled by a Mark 51 director that incorporated a Mark 14 lead-computing gyro gunsight while the sailors that used the 20 mm gun used a Mark 14 sight to track their targets.