SS Arabic was a British-registered ocean liner that entered service in 1903 for the White Star Line. She was sunk on 19 August 1915, during the First World War, by German submarine SM U-24, 50 mi (80 km) south of Kinsale, causing a major diplomatic incident.

Arabic was originally intended to be Minnewaska, one of four ships ordered from Harland and Wolff, Belfast, by the Atlantic Transport Line (ATL), but fell victim to the recession and the shipbuilding rationalization following the ATL's 1902 incorporation into the IMM Co., and was transferred before completion to the White Star Line as Arabic. She was extensively modified before launch with additional accommodation, which extended her superstructure aft of her third mast and forward of her second mast. Arabic was fitted with twin-screw propellers driven by separate sets of quadruple expansion engines arranged on the builders' "balanced" principle. She had accommodations for 1,400 passengers; 200 in first class, 200 in second class and 1,000 in third class. Her accommodations were configured similar to most other White Star passenger ships, with first class amidships, second class abaft of first, and third class divided at the fore and after ends of the vessel. She was launched in Belfast on 18 December 1902.

Arabic commenced her maiden voyage from Liverpool to New York City via Queenstown on 26 June 1903, arriving in New York on 5 July, marking the beginning of a 12-year career during which she spent half on White Star's main route between Liverpool and New York, and the other half on White Star's secondary service to Boston, both of which included stops at Queenstown. She spent her first two years on the Liverpool–New York service before being transferred to the Boston route in April 1905, on which she sailed alongside Cymric and Republic for the next two years, while returning briefly to the New York route during the winter months. In the late spring of 1907, the White Star Line started their new express service out of Southampton, to which they transferred Teutonic, Majestic, Oceanic and the newly completed Adriatic, after which Arabic was returned to the New York service to make up for this rearrangement. She remained on the New York service for the next four years, and after Olympic entered service in June 1911, she was again transferred back to the Boston route, on which she remained until White Star suspended their Liverpool–Boston service in November 1914 due to the escalation of the First World War, during which several of their ships were requisitioned by the Royal Navy. She was transferred back to the New York service in January 1915, on which she remained until the end of her career the following August. Although her career was somewhat shorter than some of her company running mates, Arabic proved to be a popular addition to the White Star Fleet, as over the duration of her career she carried a total of 94,032 passengers westbound across the Atlantic; 48,655 on the New York service and 45,377 on the Boston service, as well as an additional 50,036 passengers eastbound to Liverpool, with 30,854 coming inbound from New York and 19,182 from Boston.

On 19 August 1915, U-24 was operating south of Ireland. Two months previously, following the sinking of RMS Lusitania, the Kaiser had issued secret orders for U-boats to not attack large passenger vessels.

Arabic was sailing out from Liverpool to the United States. She was zigzagging when spotted by the German submarine, and Rudolf Schneider, commander of the sub, later said that he thought she was trying to ram his vessel. Without identifying his target, the U-boat submerged and attacked Arabic without warning, 50 mi (80 km) south of Kinsale. He fired a single torpedo which struck the liner aft, and she sank within 10 minutes, killing 44 passengers and crew, 3 of whom were American.

The US had still not fully resolved the dispute with Germany over RMS Lusitania. Indeed, the last note, of 21 July, that Wilson sent took the form of an ultimatum, to the effect that the US would regard any subsequent sinkings that harm American citizens as "deliberately unfriendly".

Advised by Colonel House, on 22 August President Wilson issued a statement via his press office to the effect that the White House staff was speculating on what to do if the Arabic investigation indicated that there had been a deliberate German attack. If true, there was speculation that the US would sever relations with Germany, while if it was untrue, negotiations were possible. Severing relations was understood to likely lead to war.

The attack was met with panic from German Chancellor Theobald von Bethmann Hollweg and the German Foreign Office under Gottlieb von Jagow. Senior staff at the Foreign Office wrote angrily: "The attacks on the SS Orduña and the Arabic prove that new incidents with America are possible at any time. [...] Both ships were torpedoed without previous warning while sailing *to* America. That the torpedo fired at the Orduna missed is only an accident." The fact that the ships were heading out from the UK undercut all of the German excuses about the Lusitania carrying munitions, and indicated that any submarine captain could cause war between Germany and the US at any time. The Chancellor and the Foreign Office agreed that cruiser rules with passenger ships was absolutely imperative.