Tehran is one of the most ethnically diverse cities in Asia. The city of Tehran (not to be confused with the larger, Tehran Metropolitan) had a population of approximately 9,729,740 in 2025 and the Tehran Province had a 14,437,000 population in 2023.
According to a 2010 census conducted by the Sociology Department of Tehran University in many districts of Tehran across various socio-economic classes in proportion to the population sizes of each district and socio-economic class, 63% of people in Tehran were born in Tehran, 98% can speak the Persian language, 75% identify themselves as ethnic Persians, and 13% have some degree of proficiency in a European language.
Azerbaijanis in Tehran also known as Turks in Tehran or Azeris in Tehran are Iranians of Azerbaijani ethnicity. Azerbaijanis comprise 25% of Tehran's population and 20.3% â 25% of Tehran Province's population.
Ethnic Mazanderanis are the third-largest, comprising about 8.2% of the total population.