Abu al-Husayn Ishaq ibn Ibrahim[1] (Arabic: أبو الحسين إسحاق بن إبراهيم, died July 850) was a ninth-century official in the service of the Abbasid Caliphate. A member of the Mus'abid family, he was related to the Tahirid governors of Khurasan, and was himself a prominent enforcer of caliphal policy during the reigns of al-Ma'mun, al-Mu'tasim, al-Wathiq, and al-Mutawakkil.[2]