RMS Mauretania was an ocean liner designed by Leonard Peskett and built by Wigham Richardson and Swan Hunter for the British Cunard Line, launched on the afternoon of 20 September 1906. She was the world's largest ship until the launch of RMS Olympic in 1910. Mauretania became a favourite among her passengers. She captured the eastbound Blue Riband on her maiden return voyage in December 1907, then claimed the westbound Blue Riband for the fastest transatlantic crossing during her 1909 season, which she held both speed records for 20 years.

The ship's name was taken from the ancient Roman province of Mauretania on the northwest African coast, not the modern Mauritania to the south. Similar nomenclature was also employed by Mauretania's running mate Lusitania, which was named after the Roman province directly north of Mauretania, across the Strait of Gibraltar in Portugal. Mauretania remained in service until September 1934, when Cunard-White Star retired her; scrapping commenced in Rosyth, in 1935.