Abū al-Ḥasan ʿAlī , (born c. 1297—died May 24, 1351, Hintato, Mor.), Marīnid sultan of Morocco (reigned 1331–51) who increased the territories of his dynasty and, for a brief time, created a united North African empire.

In 1331 Abū al-Ḥasan succeeded his father, Abū Saʿīd, to the throne. With the goals of expelling the Christians from Spain and uniting all the Islāmic lands of North Africa, Abū al-Ḥasan attacked and captured Algeciras and Gibraltar in Spain (1333). He next attacked the Algerian territories of the ʿAbd al-Wādid dynasty and after a three-year siege took the strategic town of Tlemcen (1337). Taking advantage of the internal weakness of Spain, he won a brilliant naval victory in the Strait of Gibraltar on April 5, 1340, but was defeated six months later at the Battle of Rio Salado and was forced to abandon his “holy war” against Spain.

Abū al-Ḥasan expanded his influence in Tunisia and married a daughter of Abū Bakr, the Ḥafṣid ruler of Tunisia, which by 1342 had become a virtual vassal state. After Abū Bakr’s death Abū al-Ḥasan invaded Tunisia and captured Tunis (Sept. 15, 1347), but in the following April he was badly defeated by a confederation of Tunisian tribes at Kairouan. Forced to flee Tunisia by sea during December 1349, he landed at Algeria in January and set out for Morocco to put down a rebellion led by his son Abū ʿInān. Deserted by his troops, he abdicated in favour of Abū ʿInān in 1351, and he died shortly afterward of an infected wound.