Marine Department is a term for a variety of departments, in marine science, military and maritime transport and authorities:

Government bodies and authorities Department of Marine and Fisheries and the Naval Service, Canada Department of Marine and Fisheries, Canada Department of Agriculture, Food and the Marine, Ireland Marine Department (Hong Kong) - manages the Hong Kong harbour

Marine Department (Malaysia), a federal agency in Malaysia Marine Department (New Zealand) Marine Fisheries Department, Pakistan Singapore Marine Department, now merged into the Maritime and Port Authority of Singapore

Military organisations Marine Department (Royal Navy), British Admiralty State Department Marines, USA