Al-Husayn I ibn Ali (1669 – 13 March 1740) (Arabic: حسين بن علي التركي, Ḥusayn bin ʿAlī al-Turkī; Turkish: Hüseyin bin Ali) was the founder of the Husainid Dynasty, which ruled Tunisia until 1957.
Husayn was born a "kouloughli", which is a term used to refer to a Turkish father and a local North African mother. His father was a Turk living in Crete and his mother was a Tunisian. The Husaynids were called "Greek" by Habib Bourguiba.
In 1702 the janissary commander Ibrahim Sharif, of whom he was lieutenant, expelled the Muradid Dynasty from Tunis. Three years later, after Sharif had been captured by the Dey of Algiers, he took control of the Turkish army in Tunis and, on 12 July 1705, had himself proclaimed Bey of Tunis. He had one of his close relatives proclaimed dey by the Constantinople diwan, an act which increased his popularity amongst the Turkish janissaries, and he was also able to gain support from his Tunisian subjects; however, his entourage was mostly composed of Mamluks. Husayn's first councillor was a Frenchman from Toulon, a literate man who had helped him in gaining power.
A pious man, he imposed a unity upon the country, divided into numerous different ethnicities, under the aegis of Islam and its traditions. He built numerous edifices dedicated to religion and religious studies (madrasas), such as the Madrasahs of the Dyers (1727) and al-Husseyniah in Tunis, as well as the mosque of Le Bardo and other madrasas in the country's mainland (Kairouan, Sfax, Sousse and Nafta).