希腊化时代（英语：Hellenistic period）在亚历山大征服波斯帝国之后不久开始。通常起始点视为亚历山大大帝于公元前323年逝世开始，并结束于罗马共和国在前146年征服希腊本土，或前31/30年最后继业者王国——托勒密王国灭亡为止。这段时期，19世纪后西方史学界认为古希腊文明主宰整个地中海东部沿岸的文明，所以称此地这段时期为希腊化时代。希腊化时代被认为是希腊古典时代和罗马文化间的过渡时期，与希腊古典时代相比，被认为文化上呈现下降或衰退的趋势。希腊化时期的特点是新的一波的希腊殖民活动，并主要以埃及和西亚的各希腊化王国内置立殖民城市为主。

The Hellenistic period covers the period of ancient Greek (Hellenic) history and Mediterranean history between the death of Alexander the Great in 323 BC and the emergence of the Roman Empire as signified by the Battle of Actium in 31 BC and the subsequent conquest of Ptolemaic Egypt the following year. At this time, Greek cultural influence and power was at its peak in Europe, Africa and Asia, experiencing prosperity and progress in the arts, exploration, literature, theatre, architecture, music, mathematics, philosophy, and science. For example, competitive public games took place, ideas in biology, and popular entertainment in theaters. It is often considered a period of transition, sometimes even of decadence or degeneration, compared to the enlightenment of the Greek Classical era. The Hellenistic period saw the rise of New Comedy, Alexandrian poetry, the Septuagint and the philosophies of Stoicism and Epicureanism. Greek Science was advanced by the works of the mathematician Euclid and the polymath Archimedes. The religious sphere expanded to include new gods such as the Greco-Egyptian Serapis, eastern deities such as Attis and Cybele and the Greek adoption of Buddhism.