Abu Ali al-Hassan ibn Masud al-Yusi (1631–1691) was a Moroccan Sufi writer. He is considered to be the greatest Moroccan scholar of the seventeenth century and was a close associate of the first Alaouite sultan Rashid. Al-Yusi was born in a Berber tribe, the Ait Yusi, just north of Fes. He was married to Zahra bint Muhammad b. Musa al-Fasi. Al-Yusi left his native village on a very young age for a lifelong pilgrimage. He received his barakah from Sheikh Mohammed Ben Nasir of the tariqa Nasiriyya of Tamegroute, and studied and taught at the zawiyya of Dila with Mohammed al-Hajj ibn Abu Bakr al-Dila'i.
Of his autobiography, Al-Fahrasa (literally: academic journey), only the introduction and first section have survived and these were, until recently, unpublished. His better known text Al-Muharat also contains many autobiographical passages. Both texts are remarkable for the author's frank discussions of childhood misdeeds, the pleasures of his conjugal sex life, and other intimate details of his personal life. Al-Yusi's Daliyya (poem of praise) of his shaikh Muhammad b.Nasir al-Dari of the Zawiya Nasiriyya of Tamegroute, is famous both in Morocco and West Africa.
Al-Yusi overtly criticised the reign of the Alouite sultan Moulay Ismael. This criticism was expressed in 'open' letters, some of which remain today.
Al-Yusi is especially well-known because he founded the cult of the seven saints of Marrakech at the request of Moulay Ismael.