Iran is subdivided into thirty-one provinces (Persian: استان ostân), each governed from a local centre, usually the largest local city, which is called the capital (Persian: مرکز, markaz) of that province. The provincial authority is headed by a governor-general (Persian: استاندار ostândâr), who is appointed by the Minister of the Interior subject to approval of the cabinet.^[1]

Iran has held its modern territory since the Treaty of Paris in 1857. Prior to 1937, Iran had maintained its feudal administrative divisional structure, dating back to the time the modern state was centralized by the Safavid dynasty in the 16th century. Although the boundaries, roles, and rulers changed often. On the eve of the Persian Constitutional Revolution in 1905, Iran was composed of Tehran, being directly ruled by the monarch; four eyalats (Persian: ایالات elâyât pl., ایالت elayat sin.), ruled by Qajar princes; and various velayats (Persian: ولایات velâyât pl., ولایت velayat sin.). Nomadic tribal confederations, such as the Bakhtiari people and Qashqai people, were largely independent of the domestic administrative divisions and were autonomous.

With the Constitutional Revolution, and the formation of the first National Consultative Assembly, Iran's administrative subdivisions were legally defined in 1907.^[2] Any change in the boundaries of eyalats, velayats, or their respective sub-districts was banned as per the Iranian constitution, except with the passage of a new law by the assembly. As per the 1907 law, the following were defined:^[2]

On October 22, 1911, Iranian National Consultative Assembly passed another law, titled "The law of Election of National Consultative Assembly" (Persian: قانون انتخابات مجلس شورای ملی). This law presented a complete list of all Eyalats and Velayats of the country, as well as their constituent districts and cities. This list presented the grouping of various towns and districts into electoral districts for the purpose of the election. According to this law, in 1911, Iran was made up of 27 administrative subdivisions, the region of Tehran, 4 eyalats, and 22 velayats.^[3] Below is a list:

In 1937, Iran was reorganized to form ten numbered provinces with subordinate governorates: Gilan, Mazandaran, East Azerbaijan, West Azerbaijan, Kermanshah, Khuzestan, Fars, Kerman, Khorasan, and Isfahan.^[4]

Iran has had a historical claim to Bahrain as its 14th province: Bahrain province, which was under British colonial occupation until 1971. Prior to 1957, Bahrain was placed under Fars province.^[5] During Safavid Iran, Bahrain was subordinate to Bushehr governorship and Zubarah (located in modern-day country of Qatar) was its capital city. In 1737, under Afsharid dynasty Bahrain was made subject to Fars governorship.^[6] This claim was reasserted by the new theocratic Iranian leadership after 1979 with the famous 1981 coup attempt that occurred.^[7]

From 1960 to 1981, the governorates were gradually raised to provincial status one by one. Since then several new provinces have been created, most recently in 2010 when the new Alborz province was split from Tehran province, and before that in 2004 when the province of Khorasan was divided into three provinces.^[8]

According to Donya-e-Eqtesad, between 2017 and 2019, some 11 of the 20 poorest Iranian cities were in the province of Sistan and Baluchestan. Three other markedly poor cities were located in Kerman province.^[9]

Table below shows the provinces' abbreviation, which can be used in postal addresses and academic affiliations for the sake of simplicity.

• Khorasan province
• Bahrain province

• List of current Iran governors-general
• List of Iranian provinces by Human Development Index
• Administrative divisions of Iran
  • Regions of Iran
  • Counties of Iran
• Geography of Iran
• ISO 3166-2:IR