Ship (or marine) Engineering Officers or, simply, Ship Engineers are responsible for operating the propulsion plants and support systems on board crew, passengers and cargo seafaring vessels or other watercraft. Alternative terms commonly employed to collectively refer to the profession are seagoing or seafaring engineer officers. In the United States they are usually trained via cadet ships sponsored by a variety of maritime organizations. Engineering Officer Cadets of most countries are sponsored during training by a shipping company, serving their time on board ships owned by that company. Many go on to work as Engineering Officers with their sponsoring company once training is complete.

This article largely pertains to design engineering. For the operating engineer, see marine engineer.

Marine engineering often refers to the engineering of boats, ships, oil rigs and any other marine vessel or structure, but also encompasses oceanographic engineering. Specifically, marine engineering is the discipline of applying engineering sciences, and can include mechanical engineering, electrical engineering, electronic engineering, and computer science, to the development, design, operation and maintenance of watercraft propulsion and also on-board systems and oceanographic technology, not limited to just power and propulsion plants, machinery, piping, automation and control systems etc. for marine vehicles of any kind like surface ships, submarines etc..