This chapter offers insight into how ships are designed by naval architects to address the ever-growing demand for maritime transportation. The terminology associated with ships is introduced, together with some of the main design characteristics of ships. The stability of marine vessels at both small and large angles of heel is explored. Furthermore, the main resistance and propulsion concepts that must be utilized effectively to ensure that the vessel can achieve its target speed are presented. Elements of ship structure as well as structural design and optimization considerations are discussed. Finally, additional aspects that impact ship design are outlined, including the environment, seakeeping, maneuverability, and damage stability.