Abū al-Qāsim Kathīr, Manṣūr b. Muḥammad b. Kathīr, entitled Shaykh al-ʿAmīd (d. after 432/1041), was dīwān-sālār (minister of the court) and a vizier under the Ghaznawids.

His father, Abū al-Ḥusayn Muḥammad, was an important figure in the government of Abū ʿAlī Sīmjūr (q.v.), the Sāmānid commander-in-chief (sipahsālār) in Khurāsān (Bayhaqī, 206) who also held the position of vizier under the Sāmānids (al-Thaʿālibī, 2/108). His grandfather, Kathīr b. Aḥmad, had also been in the service of Abū al-Ḥasan Sīmjūr (q.v.), who proved himself to be …