Littorio was the lead ship of her class of battleship; she served in the Italian Regia Marina (Royal Navy) during World War II.

Shortly after her commissioning, Littorio was badly damaged during the British air raid on Taranto on 11 November 1940, which put her out of action until the following March.

During the German attack, which saw the destruction of her sister Roma, Italia herself was hit by a Fritz X radio-controlled bomb, causing significant damage to her bow.

As part of the armistice agreement, Italia was interned at Malta, Alexandria, and finally in the Great Bitter Lake in the Suez Canal, where she remained until 1947.

Her secondary anti-surface armament consisted of twelve 152 mm (6 in) /55 Model 1934/35 guns in four triple turrets placed at the corners of the superstructure.

[8] Changes to the design and a lack of armor plating led to delays in the building schedule, causing a three-month slip in the launch date from the original plan of May 1937.

She was commissioned on 6 May 1940, and after running additional trials that month, she transferred to Taranto where she—along with Vittorio Veneto—joined the 9th Division under the command of Rear Admiral Carlo Bergamini.

[10] On 31 August – 2 September 1940, Littorio sortied as part of an Italian force of five battleships, ten cruisers, and thirty-four destroyers to intercept British naval forces taking part in Operation Hats and Convoy MB.3, but contact was not made with either group due to poor reconnaissance and no action occurred.

[6][11] A similar outcome resulted from the movement against British Operation "MB.5" on 29 September - 1 October; Littorio, four other battleships, eleven cruisers, and twenty-three destroyers had attempted to intercept the convoy carrying troops to Malta.

Twenty-one Swordfish torpedo bombers launched from the aircraft carrier HMS Illustrious attacked the Italian fleet in two waves.

The two forward hits caused major flooding and led her to settle by the bows, with her decks awash up to her main battery turrets.

[17] On 13 December, she participated in another sweep to catch a convoy to Malta, but the attempt was broken off after Vittorio Veneto was torpedoed by a British submarine.

[16] By late 1941, British success at breaking the Enigma code made it increasingly difficult for Axis convoys to reach North Africa.

On 22 March, she participated in the Second Battle of Sirte, as the flagship for an Italian force attempting to destroy a British convoy bound for Malta.

[20] As the destroyers withdrew, one of them hit Littorio with a single 4.7-inch (120 mm) shell, which caused minor damage to the ship's fantail.

[24] The British quickly located the approaching Italian fleet and launched several night air strikes in an attempt to prevent them from reaching the convoy, though the aircraft scored no hits.

[24][26] At 14:00, the Italians broke off the chase and returned to port; shortly before midnight that evening, Littorio was struck by a torpedo dropped by a British Wellington bomber, causing some 1,500 long tons (1,500 t) of water to flood the ship's bow.

While en route, the German Luftwaffe (Air Force) attacked the Italian fleet using Dornier Do 217s armed with Fritz X radio-controlled bombs.

In the Treaty of Peace with Italy, signed five days later on 10 February, Italia was allocated as a war prize to the United States.