Iranian Azerbaijan (Persian: آذربایجان ایران; Āzarbāyjān-e Irān), also known as Southern Azerbaijan or South Azerbaijan (Azeri: گوني اذربایجان, Güney Azərbaycan), is a region in the northwest of Iran, approximately consisting of the provinces of Ardebil, East Azarbaijan, West Azarbaijan and Zanjan. Iranian Azerbaijan is the officially recognized and accepted name. South Azerbaijan, on the other hand, is popular among Azerbaijani nationalists, although it is historically and politically questionable.

This is the area that was historically named Azarbaijan/Azerbaijan, from which the Republic of Azerbaijan (which became the Azerbaijan SSR later and then the Republic of Azerbaijan again) took its name when it was formed as independent state with the help of the Ottomans in 1918. The new republic consisted of three former provinces of Aran, Shervan and Talish-i Gushtasbi which were taken by Russia in the Persia-Russia Wars.

Iranian Azerbaijan has an area of 176,512 square kilometers and a population of about 16 million (estimates vary). Iranian Azerbaijan is famous for its great nature beauty. There are 17 rivers and two lakes in the region. Cotton, nuts, textiles, tea, machinery and electrical equpiments are main industries.

Major cities include Tabriz, Urmia, Ardabil, Maragheh, Marand and Zanjan.