The Mediterranean Sea ( MED-ih-tə-RAY-nee-ən) is an intercontinental sea situated between Europe, Asia, and Africa. It is surrounded by the Mediterranean basin and almost completely enclosed by land: on the east by the Levant in West Asia, on the north by Anatolia in West Asia and Southern Europe, and on the south by North Africa. To its west it is connected to the Atlantic Ocean via the Strait of Gibraltar that separates the Iberian Peninsula in Europe from Morocco in Africa by only 14 km (9 mi); additionally, it is connected to the Black Sea through the Bosporus strait that intersects Turkey in the northeast and the Red Sea via the Suez Canal in the southeast.

The Mediterranean Sea covers an area of about 2,500,000 km² (970,000 sq mi), representing 0.7% of the global ocean surface; it includes fifteen marginal seas, including the Aegean, Adriatic, Tyrrhenian, and Marmara. Geological evidence indicates that around 5.9 million years ago, the Mediterranean was cut off from the Atlantic and was partly or completely desiccated over a period of some 600,000 years during the Messinian salinity crisis before being refilled by the Zanclean flood about 5.3 million years ago.

The history of the Mediterranean region is crucial to understanding the origins and development of many modern societies; it is sometimes described as an "incubator of Western civilization". and saw the emergence of some of the earliest and most advanced civilisations, including those of Egypt, Greece, and the Fertile Crescent. The Levant in the Eastern Mediterranean was among the first regions in the world to display permanent human habitation as early as 12,000 BC. The Mediterranean Sea was an important route for merchants, travellers, and migrants in antiquity, facilitating trade and cultural exchange between various peoples as well as colonisation and conquest. The Roman Empire maintained nautical hegemony over the sea for centuries and is the only state to have ever controlled all of its coast.

The Mediterranean Sea has an average depth of 1,500 m (4,900 ft) and the deepest recorded point is 5,109 ± 1 m (16,762 ± 3 ft) in the Calypso Deep in the Ionian Sea.