The Sixth Fleet is the United States Navy's operational fleet and staff of United States Naval Forces Europe. The Sixth Fleet is based in Naples, Italy.

The Sixth Fleet conducts the full range of Maritime Operations and Theater Security Cooperation missions in concert with coalition, joint, interagency and other parties in order to advance security and stability in Europe and Africa. The commander of the Sixth Fleet is Vice Admiral Frank Craig Pandolfe.

The United States has maintained a naval presence in the Mediterranean since the early 19th century, when U.S. Naval forces first engaged the Barbary Pirates to prevent them from interfering with commercial shipping. The earliest unit was the Mediterranean Squadron.

In 1946, President Truman dispatched the battleship Missouri to the Eastern Mediterranean to counter Soviet threats to Turkey and Iran. The small fleet maintained in the Mediterranean by U.S. Naval Forces, Eastern Atlantic and Mediterranean was known as Naval Forces Mediterranean and had as its flagship, a destroyer tender, anchored at Naples, Italy. The cruiser Dayton relieved the tender Shenandoah as flagship and began operating with the fleet. The title of Naval Forces Mediterranean was changed to Commander Sixth Task Fleet and then, in 1950, Commander, Sixth Fleet.