The traditional geographic regions of Greece (Greek: γεωγραφικά διαμερίσματα, literally "geographic departments") are the country's main historical-geographic regions, and were also official administrative regional subdivisions of Greece until the 1987 administrative reform. Despite their replacement as first-level administrative units by the newly defined administrative regions (Greek: περιφέρειες), the nine traditional geographic divisions—six on the mainland and three island groups—are still widely referred to in unofficial contexts and in daily discourse.
As of 2011, the official administrative divisions of Greece consist of 13 regions (Greek: περιφέρειες)—nine on the mainland and four island groups—which are further subdivided into 74 regional units and 325 municipalities. Formerly, there were also 54 prefectures or prefectural-level administrations.
The regions shown on the map but not in the list are geographic regions, but they are not major.