The second major element of the population is composed of various Turkic-speaking groups. The Turkic languages belong to the Ural-Altaic family, which includes many languages of Soviet Central Asia and western China, as well as Turkish, Hungarian, and Finnish. The various Turkic languages spoken in Iran tend to be mutually intelligible. Of these, only Azarbaijani is written to any extent. In Iran it is written in the Arabic script, in contrast to the Azarbaijani in Turkey, which is written in the Roman script, and that of the Soviet Union, which is written in the Cyrillic script. Unlike Indo-European languages, Turkic languages are characterized by short base words to which are added numerous prefixes and suffixes, each addition changing the meaning of the base. They are also distinguished by their vowel harmony, which means that the kind of vowel used in the base word and the additives must agree. Thus, lengthy words might be filled with "o's" and "u's" or with "a's" and "e's," but not with mixtures of the two.

Turkic speakers make up as much as 25 percent of Iran's total population. They are concentrated in northwestern Iran, where they form the overwhelming majority of the population of East Azarbaijan and a majority of West Azarbaijan. They also constitute a significant minority in the provinces of Fars, Gilan, Hamadan, Khorasan, Mazandaran, and Tehran. Except for the Azarbaijanis, most of the Turkic groups are tribally organized. Some of the Turkic tribes continue to follow a nomadic or seminomadic life. Educated Turkic speakers in the large cities speak and understand Persian.

Data as of December 1987