The Greco-Roman civilization (; also Greco-Roman culture; spelled Graeco-Roman in the Commonwealth), as understood by modern scholars and writers, includes the geographical regions and countries that culturally—and so historically—were directly and intimately influenced by the language, culture, government and religion of the Greeks and Romans. A better-known term is classical antiquity. In exact terms the area refers to the "Mediterranean world", the extensive tracts of land centered on the Mediterranean and Black Sea Basins, the "swimming pool and spa" of the Greeks and the Romans, in which those peoples' cultural perceptions, ideas, and sensitivities became dominant in classical antiquity.

That process was aided by the universal adoption of Greek as the language of intellectual culture and commerce in the Eastern Mediterranean and of Latin as the language of public administration and of forensic advocacy, especially in the Western Mediterranean.

Greek and Latin were never the native languages of many or most of the rural peasants, who formed the great majority of the Roman Empire's population, but they became the languages of the urban and cosmopolitan elites and the Empire's lingua franca, even if only as corrupt or multifarious dialects for those who lived within the large territories and populations outside the Macedonian settlements and the Roman colonies. All Roman citizens of note and accomplishment, regardless of their ethnic extractions, spoke and wrote in Greek or Latin. Examples include the Roman jurist and imperial chancellor Ulpian, who was of Phoenician origin; the mathematician and geographer Claudius Ptolemy, who was of Greco-Egyptian origin; and the famous post-Constantinian thinkers John Chrysostom and Augustine, who were of Syrian and Berber origins respectively. Note too the historian Josephus Flavius, who was of Jewish origin but spoke and wrote in Greek.