The Tats (Tati: IrünàTâtün, ) are an Iranian people living in northern Iran, especially in Qazvin province.
The Tats of Iran are mainly Muslim and number about 300,000.
Starting from the Middle Ages, the term Tati was used not only for the Caucasus but also for northwestern Iran, where it was extended to almost all of the local Iranian languages except Persian and Kurdish.
The Tats of Iran use the Tati language, a group of northwestern Iranian dialects which are closely related to the Talysh and Zaza. Persian and Azerbaijani are also spoken.
Currently, the term Tati and Tati language is used to refer to a particular group of north-western Iranian dialects (Chali, Danesfani, Hiaraji, Hoznini, Esfarvarini, Takestani, Sagzabadi, Ebrahimabadi, Eshtehardi, Hoini, Kajali, Shahroudi, Harzani) in Iranian Azerbaijan, as well as south of it in the provinces of Qazvin and Zanjan. These dialects have a certain affinity to the Talysh language, Mazanderani language and may be descendants of the extinct Old Azari language.