The Superliner is a largely disabled-accessible double decker passenger car used by Amtrak, mainly on its western routes. They come in coach, baggage coach, diner, lounge, coach cafe, sleeper, and transition car/dorm configurations. Trains using Superliners include the Capitol Limited, Auto Train, Sunset Limited, Texas Eagle, California Zephyr, City of New Orleans, Southwest Chief, Empire Builder, Heartland Flyer and Coast Starlight.

"Superliner" is a term sometimes used for an ocean liner of over 10,000 gross tons. The term was coined in the late 19th century, when ocean liners were rapidly increasing in size and speed. Superliners were the primary means of intercontinental travel in the first half of the twentieth century, as passengers favoured large, fast ships.