The history of Iran is intertwined with that of Greater Iran, a sociocultural region spanning the area between Anatolia in the west and the Indus River and Syr Darya in the east, and between the Caucasus and Eurasian Steppe in the north and the Persian Gulf and the Gulf of Oman in the south. Central to this area is the modern-day country of Iran, which covers the bulk of the Iranian plateau.

Greater Iran or Greater Persia, also called the Iranosphere or the Persosphere, is an expression that denotes a wide socio-cultural region comprising parts of West Asia, the Caucasus, Central Asia, South Asia, and East Asia —all of which have been impacted, to some degree, by the Iranian peoples and the Iranian languages. It is defined by having been long-ruled by the dynasties of various Iranian empires, under whom the local populaces gradually incorporated some degree of Iranian influence into their cultural and/or linguistic traditions; or alternatively as where a considerable number of Iranians settled to still maintain communities who patronize their respective cultures, geographically corresponding to the areas surrounding the Iranian plateau. It is referred to as the "Iranian Cultural Continent" by Encyclopædia Iranica.