The majority and state religion of Iran is Shia Islam.

Religious minorities include:

Sunni Muslims are accepted as fellow Muslims, while Christians, Jews, and Zoroastrians are recognised as People of the Book and have certain legal rights insofar as members of these religions are born and brought up within their religion. The constitution of the Islamic Republic of Iran recognizes Islam, Christianity, Judaism, and Zoroastrianism as official religions. No other religious practice is allowed in Iran.

Conversion from Islam to any of these religions is considered apostasy and can under the current government result in harassment and religious persecution.

Many Sufi sects are active within Iran. Examples are Sheykhi centred around Kerman and Naqshbandi mostly in the Azeri regions of Iran. They are considered muslims by the government.