RMS Adriatic was an ocean liner of the White Star Line. She was the fourth of a quartet of ships measuring over 20,000 tons, dubbed The Big Four. The ship was the only one of the four which was never the world's largest ship; however, she was the fastest of the Big Four. The Adriatic was the first ocean liner to have an indoor swimming pool and a Turkish bath.

She was built by Harland and Wolff and was launched on 20 September 1906 (the same day as the Cunard Line's Mauretania). When she was completed, she was 75 ft wide (23 m). She set off on her maiden voyage from Liverpool to New York on 8 May 1907 under the command of Captain Edward Smith. She was changed to the Southampton run after her maiden voyage. She was, however, the ship that inaugurated White Star's Southampton service and was the first White Star liner to use the newly constructed dock in Southampton, named the White Star Dock (it was renamed in 1922 to the Ocean Dock). She ran this route until 1911 when Olympic took it over with the Adriatic returning to the Liverpool run.

During World War I, the Adriatic served as a troopship and survived the war without incident. After the war ended, she returned to passenger service. In 1928, she was converted to a "cabin-class" ship. In 1933, she was withdrawn from the North Atlantic route and was converted into cruising.

The Adriatic left Liverpool for the last time on 19 December 1934, her longest voyage ever, to be scrapped at Onomichi, Japan, in 1935. She is also the ship that brought RMS Titanic survivor, Millvina Dean, home to England from the United States in 1912. Millvina was the youngest passenger on the Titanic's fateful voyage and the Titanic's last living survivor having died in 2009.