Sajah bint al-Harith ibn Suaeed (Arabic: سجاح بنت الحارث بن سويد) from tribe of Banu Tamim was Arab Christian protected first by her tribe then cause a split within Banu Tamim and finally defended by Banu Hanifa. Her father, Al-Haris, belonged to the Bani Yarbu section of the Bani Tamim tribe. Her mother belonged to the Banu Taghlib tribe of Iraq.
During the apostasy movement which emerged following the death of Muhammad, Sajah declared she was a prophetess after learning that Musaylimah and Tulayha had declared prophethood. Before claiming to be a prophetess, Sajah had a reputation as a soothsayer. Thereafter, 4,000 people gathered around her to march on Medina. Others joined her against Medina. However, her planned attack on Medina was called off after she learned that the army of Khalid ibn al-Walid had defeated Tulayha al-Asadi (another self-proclaimed prophet). Thereafter, she sought cooperation with Musaylimah to oppose the threat of Khalid. A mutual understanding was initially reached with Musaylimah. However, Sajah later married Musaylimah and accepted his self-declared prophethood. Khalid then crushed the remaining rebellious elements around Sajah, and then moved on to crush Musaylimah. After the Battle of Yamama where Musaylimah was killed, Sajah converted to Islam.