Gölcük Naval Base () is the main base of the Turkish Navy on the east coast of the Sea of Marmara in Gölcük, Kocaeli. It is the principal base for logistic support with various facilities stretched over of land. In addition to the workplaces, the base houses apartment-like barracks, social facilities, a military hospital, a military museum and an archive for naval history. The shipyard at the base is capable of constructing frigates, submarines, fast attack boats and auxiliary vessels with high technology in recognized standards.