RMS Baltic was an ocean liner of the White Star Line that sailed between 1904 and 1932. At 23,876 gross register tonnage, she was the world's largest ship until May 1906. She was the third of a quartet of ships, all measuring over 20,000 gross register tons, dubbed The Big Four, the other three being RMS Celtic, RMS Cedric, and RMS Adriatic.

The White Star Line was a British shipping line. Founded out of the remains of a defunct packet company, it gradually rose up to become one of the most prominent shipping companies in the world, providing passenger and cargo services between the British Empire and the United States. While many other shipping lines focused primarily on speed, White Star branded their services by focusing more on providing comfortable passages for both upper class travellers and immigrants.