A training ship is a ship used to train students as sailors. The term is mostly used to describe ships employed by navies to train future officers. Essentially there are two types: those used for training at sea and old hulks used to house classrooms. As with receiving ships or accommodation ships, which were often hulked warships in the 19th Century, when used to bear on their books the shore personnel of a naval station, that were generally replaced by shore facilities commissioned as stone frigates, most "Training Ships" of the British Sea Cadet Corps, by example, are shore facilities.

From its modern interpretations to its antecedents when maritime nations would send young naval officer candidates to sea, sail training provides an unconventional and effective way of building many useful skills on and off the water.