Bab Bachir (Arabic: باب بشير) (died 1254) was a slave consort of the last Abbasid caliph, al-Musta'sim (r. 1242–1258) and mother of Abu Nasr Muhammad ibn al-Musta'sim. She was a slave bought to the Abbasid harem by the Caliph. When she gave birth to a son, prince Abu Nasr Muhammad, she became an umm walad and was manumitted by the Caliph, who married her. After her marriage, she made herself known for her public charitable initiatives, which was a common method for the consorts of the Caliph (who could not leave the harem), to make themselves known.