The Greco-Roman world, Greco-Roman culture, or the term Greco-Roman ( /ˌɡrɛkoʊˈroʊmən/ or /ˌɡrɛkəˈroʊmən/; spelt Graeco-Roman in the United Kingdom and the Commonwealth), when used as an adjective, as understood by modern scholars and writers, refers to those geographical regions and countries that culturally (and so historically) were directly, protractedly and intimately influenced by the language, culture, government and religion of the ancient Greeks and Romans. 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 Romans, i.e. one wherein the cultural perceptions, ideas and sensitivities of these peoples were dominant.

As mentioned, the term Greco-Roman world describes those regions who were for many generations subjected to the government of the Greeks and then the Romans and thus accepted or at length were forced to embrace them as their masters and teachers. This process was aided by the seemingly universal adoption of Greek as the language of intellectual culture and at least Eastern commerce, and of Latin as the tongue for public management and forensic advocacy, especially in the West (from the perspective of the Mediterranean Sea). Though these languages never became the native idioms of the rural peasants (the great majority of the population), they were the languages of the urbanites and cosmopolitan elites, and at the very least intelligible (see lingua franca), if only as corrupt or multifarious dialects to those who lived within the large territories and populations outside of the Macedonian settlements and the Roman colonies. Certainly, all men of note and accomplishment, whatever their ethnic extractions, spoke and wrote in Greek and/or Latin.

The Roman Empire (Latin: IMPERIVM ROMANVM) was the post-Republican period of the ancient Roman civilization, characterised by an autocratic form of government and large territorial holdings in Europe and around the Mediterranean.

The 500-year-old Roman Republic, which preceded it, had been weakened and subverted through several civil wars. Several events are commonly proposed to mark the transition from Republic to Empire, including Julius Caesar's appointment as perpetual dictator (44 BC), the Battle of Actium (2 September 31 BC), and the Roman Senate's granting to Octavian the honorific Augustus (16 January 27 BC).

Roman expansion began in the days of the Republic, but the Empire reached its greatest extent under Emperor Trajan: during his reign (98 to 117 AD) the Roman Empire controlled approximately 6.5 million km² of land surface. Because of the Empire's vast extent and long endurance, the institutions and culture of Rome had a profound and lasting influence on the development of language, religion, architecture, philosophy, law, and forms of government in the territory it governed, particularly Europe, and by means of European expansionism throughout the modern world.