The Hellenistic period of Ancient Greek history was the period between the death of Alexander the Great (Alexander III of Macedon) in 323 BC and the annexation of the Greek peninsula and islands by Rome in 146 BC. Although the establishment of Roman rule did not break the continuity of Hellenistic society and culture, which remained essentially unchanged until the advent of Christianity, it did mark the end of Greek political independence.

During the Hellenistic period the importance of "Greece proper" (that is, the territory of modern Greece) within the Greek-speaking world declined sharply. The great centers of Hellenistic culture were Alexandria and Antioch, capitals of Ptolemaic Egypt and Seleucid Syria respectively. See Hellenistic civilization for the history of Greek culture outside of Greece in this period.