SS Megantic was a British transatlantic ocean liner that was built in Ireland and launched in 1908. She was one of a pair of sister ships that were ordered in 1907 by Dominion Line but completed for White Star Line.

Before the First World War her regular route was between Liverpool and Quebec City. She and her sister Laurentic were the largest ships on the route between Great Britain and Canada.

During the First World War, Megantic served as a troop ship from 1915.

Megantic was refitted in 1919 and 1924. In the 1920s and early 1930s her duties were a mixture of liner services and cruising. In 1928 Megantic's regular route was between Great Britain and New York.

Megantic was laid up in 1931 and scrapped in 1933.

The Dominion Line operated a transatlantic liner service between Liverpool, Quebec, Montreal and Boston. In 1902 the International Mercantile Marine Company (IMM) took over Dominion Line.

In 1905 the rival Allan Line introduced the World's first steam turbine ocean liners. RMS Victorian and Virginian were two of the swiftest ships on the route between Britain and Canada, and at more than 10,600 GRT each they were also the largest. The pair made such an impression that Allan Line won a valuable Canadian Government mail contract before the ships were even launched.

But like all of the earliest turbine ships, Victorian and Virginian had direct drive from their turbines to their propellers. On Virginian this caused cavitation. Virginian also acquired a reputation for rolling excessively in heavy seas. Also, the earliest steam turbines used more bunker fuel than triple- or quadruple-expansion steam engines.