RMS Queen Mary is a retired ocean liner that sailed primarily in the North Atlantic Ocean from 1936 to 1967 for the Cunard Line (known as Cunard-White Star when the vessel entered service). Built by John Brown & Company in Clydebank, Scotland, Queen Mary along with her sister ship, the RMS Queen Elizabeth, were built as part of Cunard's planned two-ship weekly express service between Southampton, Cherbourg, and New York City. The two ships were a British response to the superliners built by German and French companies in the late 1920s and early 1930s. Queen Mary was the flagship of the Cunard Line from May 1936 until October 1946 when she was replaced by Queen Elizabeth. She also held the Blue Riband from 1936?1937 and 1938?1952.

Queen Mary sailed on her maiden voyage on 27 May 1936 and captured the Blue Riband in August of that year; she lost the title to the SS Normandie in 1937 and recaptured it in 1938. With the outbreak of World War II, she was converted into a troopship and ferried Allied soldiers for the duration of the war. Following the war, Queen Mary was refit for passenger service and along with Queen Elizabeth commenced the two-ship transatlantic passenger service that the two ships were initially built for. The two ships dominated the transatlantic passenger transportation market until the dawn of the jet age in the late 1950s. By the mid-1960s the ship was aging and though still among the most popular transatlantic liners, was operating at a loss.

After several years of decreased profits for Cunard Line, Queen Mary was officially retired from service in 1967. She sailed to the port of Long Beach, California, United States, where she remains permanently moored. Much of her machinery including her propellers and boilers were removed, and the ship now serves as a tourist attraction featuring restaurants, a museum, and hotel. The ship is listed on the National Register of Historic Places.