Glentmar Compania Maritima S.A. is a ship management and brokering company that covers all aspects of the shipping business including vessel management, chartering, sale and purchase, operations, insurance, manning, technical maintenance and financing arrangements.

The company was founded in 1968 by George K. Lentoudis. After a long and successful career in real estate and construction in the Athens area, the Lentoudis family invested in shipping when they joined with partners to acquire two vessels. The profitable results of using these vessels for trading encouraged further reinvestment, ultimately leading to the acquisition of four additional vessels using accumulated profits. In 1980, due to George Lentoudis' health concerns, his son, Konstantinos, took advantage of a strong market and sold the majority of their vessels leaving the company with one vessel under its complete control.

In 1981, Konstantinos was called upon to inherit his father's duties in the management of Glentmar along with the responsibility of continuing its commercial activities. Konstantinos completed his shipping studies in London, specifically at the London School of Foreign Trade and London Polytechnic. He then went on to gain practical experience after being employed by chartering and insurance brokers in London. He also gained valuable hands-on training while on-board vessels at sea.

Konstantinos Lentoudis revived Glentmar in 1985. The commencement of business activities coincided with an extremely serious shipping crisis during 1984 - 1985. Despite the difficult circumstances, he managed to organize a strong and competent team, comprised of executives with deep shipping knowledge and experience.