By far the largest Turkic-speaking group are the Azarbaijanis, who account for over 85 percent of all Turkic speakers in Iran. Most of the Azarbaijanis are concentrated in the northwestern corner of the country, where they form the majority population in an area between the Caspian Sea and Lake Urmia and from the Soviet border south to the latitude of Tehran. Their language, Azarbaijani (also called Azeri or Turkish), is structurally similar to the Turkish spoken in Turkey but with a strikingly different accent. About half of all Azarbaijanis are urban. Major Azarbaijani cities include Tabriz, Urmia, Ardabil, Zanjan, Khoy, and Maragheh. In addition, an estimated one-third of the population of Tehran is Azarbaijani and there are sizable Azarbaijani minorities in other major cities, such as Hamadan, Karaj, and Qazvin. The life styles of urban Azarbaijanis do not differ from those of Persians, and there is considerable intermarriage among the upper classes in cities of mixed populations. Similarly, customs among Azarbaijani villagers do not appear to differ markedly from those of Persian villagers. The majority of Azarbaijanis, like the majority of Persians, are Shia Muslims. A tiny minority of Azarbaijanis are Bahais (see Non-Muslim Minorities , this ch.).

Data as of December 1987