A ghost ship, also known as a phantom ship, is a vessel with no living crew aboard; it may be a fictional ghostly vessel, such as the Flying Dutchman, or a physical derelict found adrift with its crew missing or dead, like the Mary Celeste. The term is sometimes used for ships that have been decommissioned but not yet scrapped, as well as drifting boats that have been found after breaking loose of their ropes and being carried away by the wind or the waves.

In maritime law, flotsam, jetsam, lagan, and derelict are specific kinds of shipwreck. The words have specific nautical meanings, with legal consequences in the law of admiralty and marine salvage. A shipwreck is defined as the remains of a ship that has been wrecked, whether it has sunk or is floating on the surface of the water.