Musa ibn al-Ma'mun al-Bata'ihi (died 1192) was the son of the Fatimid vizier al-Ma'mun al-Bata'ihi (executed 1128) who wrote a biography of his father. It survives only in fragments quoted by later authors, but is a key source for the history of early 12th-century Egypt, especially for unique details such as court ceremonies. When al-Ma'mun was raised to the vizierate in 1122, Musa and his three brothers received robes of honour from the caliph. Al-Ma'mun also tried to ensure his sons in the case of his own death, having Caliph al-Amir pledge to look after them should he die. Ibn al-Bata' survived his father's downfall and execution, and died in 1192.
The fragments were collected and published by A. F. Sayyid in Passages de la Chronique d’Egypte d’Ibn al-Maʾmūn, Cairo 1983.