| Religion: | Islam |
| Honorific Prefix: | Sidi |
| Mahrez ben Khalaf Arabic: سيدي محرز بن خلف | |
| Birth Date: | 951 |
| Birth Place: | Aryanah |
| Death Date: | 1022 |
| Death Place: | Tunis |
| Resting Place: | Sidi Mahrez Mausoleum |
| Denomination: | Sunni |
| Jurisprudence: | Maliki |
| Creed: | Ash'ari |
| Influences: | Abu Bakr al-Abhari |
| Influenced: | Sidi Ben Arous |
Sidi Mahrez ben Khalaf or Abu Mohamed Mahrez ben Khalaf ben Zayn (Arabic: سيدي محرز بن خلف; 951–1022) was a Tunisian Wali, scholar of the Maliki school of jurisprudence and a Qadi. He is considered to be the patron-saint of the city of Tunis.
He was born in Ariana to a father of Arab origin who traced his lineage to Abu Bakr.[1] He studied in Kairouan and then in Fatimid-Egypt and became a teacher of Maliki jurisprudence upon his return. At the age of 57, he left his home-town (Ariana) and went into seclusion in Carthage. In c. 1014 he settled in Tunis, in a house in Bab Souika, which would become his mausoleum and later the Sidi Mahrez Mosque.[2]
He proposed to his teacher Ibn Abi Zayd al-Qayrawani (922 – 996 CE) to write a aqidah and fiqh education book, and his proposal was concretised under the title Risala fiqhiya.[3]