Efthymios (Thimio) E. Mitropoulos (Greek: Ευθύμιος Μητρόπουλος; born 30 May 1939 in Piraeus, Greece[1]) was the seventh Secretary-General of the International Maritime Organization (IMO), a United Nations agency.

[3][4] Mitropoulos was an accomplished chief engineer officer, coast guard officer, rear admiral, shipping economist, marine technologist, harbor master, lecturer, chancellor, chairman, and author of books about shipping economics and policy, merchant vessels, and navigation safety, among other shipping-related subjects.

[1] Mitropoulos's father was a merchant navy chief engineer officer and a mother was the daughter of a shipmaster and owner of brigantines and schooners.

Among his achievement included the laying down of the foundation for establishing the Joint Maritime and Aeronautical Search and Rescue Centre of Greece.

Among them was for being the author of the book Tankers: Evolution and technical issues, which won him the first prize during the Year of Shipping panhellenic competition in 1969.