Macedonia is a geographic and former administrative region of Greece, in the southern Balkans. Macedonia is the largest and second-most-populous geographic region in Greece, with a population of 2.36 million. It is highly mountainous, with major urban centres such as Thessaloniki and Kavala being concentrated on its southern coastline. Together with Thrace, along with Thessaly and Epirus occasionally, it is part of Northern Greece. Greek Macedonia encompasses entirely the southern part of the wider region of Macedonia, making up 51% of the total area of that region. Additionally, it widely constitutes Greece's borders with three countries: Albania to the northwest, North Macedonia to the north, and Bulgaria to the northeast.

Macedonia, also called Macedon, was an ancient kingdom on the periphery of Archaic and Classical Greece, which later became the dominant state of Hellenistic Greece. The kingdom was founded and initially ruled by the royal Argead dynasty, which was followed by the Antipatrid and Antigonid dynasties. Home to the ancient Macedonians, the earliest kingdom was centered on the northeastern part of the Greek peninsula, and bordered by Epirus to the southwest, Illyria to the northwest, Paeonia to the north, Thrace to the east and Thessaly to the south.