(Arabic: “master,” or “lord”), Arabic title of respect, sometimes restricted, as is the title sharīf, to the Banū Hāshim, members of Muḥammad's clan; in particular, the descendants of Muḥammad's uncles al-ʿAbbās and Abū Ṭālib and of ʿAlī ibn Abī Ṭālib by Muḥammad's daughter Fāṭimah. In the Hejaz, sayyid is further restricted to the descendants of Ḥusayn, the younger son of ʿAlī and Fāṭimah.

In Pakistan and India sayyids are numerous, being one of the four main groups of Muslims. They also constitute an influential extratribal class in Yemen, claiming descent from the Prophet through an ancestor who came south from Iraq more than a millennium ago. Many dynasties have also claimed to be sayyids in the restricted sense.