The Talysh people (Tolışon تالشان) are an Iranian ethnic group indigenous to the Talish region shared between Azerbaijan and Iran which spans the South Caucasus and the southwestern shore of the Caspian Sea. They speak the Talysh language, one of the Northwestern Iranian languages. It is spoken in the northern regions of the Iranian provinces of Gilan and Ardabil and the southern parts of the Republic of Azerbaijan. The areas in the Republic of Azerbaijan where Northern Talysh is spoken was historically known as Talish-i Gushtasbi. In Iran there is a Talesh County in Gilan Province.
The Talyshis have traditionally inhabited the Talish district in the southwestern part of the Caspian Sea, which is usually considered to extend more than 150 km. Today, the northern part of Talish is located in the Republic of Azerbaijan, encompassing the districts of Lankaran, Astara, Lerik, Masally, and Yardimli. The southern part of Talish encompasses the western part of the Gilan province of Iran, extending to the village of Kapurchal.
It is challenging to determine the Talyshis origin because so little is known about them prior to the modern era. Like other ethnonyms, the name Tāliš cannot be established with certainty. It appears in early Arabic sources as al-Țaylasān. According to Al-Tabari (died 923); "In the mountains surrounding Azarbaijan there used to live such peoples as the Gels and the al-Taylasan, who did not obey the Arabs and mastered their freedom and independence". In Persian, they are called Țālišān and Țavāliš, both plural versions of Tāliš. The native transliteration of Tāliš first appears in the 16th-century, in the Armenian version of the Alexander Romance; "And he related that he is a refugee from the Caspian gates, near the country of Talish, in the province of Gilan."
Local Talysh experts commonly claim that the Talyshis are descended from the Cadusii, an ancient tribe which inhabited the district.