The term Greater Serbia or Great Serbia () describes the Serbian nationalist and irredentist ideology of the creation of a Serb state which would incorporate all regions of traditional significance to Serbs, a South Slavic ethnic group, including regions outside modern-day Serbia that are partly populated by Serbs. The initial movement's main ideology (Pan-Serbism) was to unite all Serbs (or all territory historically ruled or populated by Serbs) into one state, claiming, depending on the version, different areas of many surrounding countries.