Abu'l-Abbas Muhammad ibn Abdallah ibn Tahir (Arabic: محمد بن عبدالله بن طاهر) (824/5 – November 867) was a Tahirid family member, who served the Abbasid Caliphate as governor and chief of police (sahib al-shurta) of Baghdad from 851 until his death, during a particularly troubled period in the city's history, which included its siege during the civil war of 865–866, in which he played a major role.
In the latter, Gurgan and Tabaristan, he had appointed his brother Sulayman, whose administration was so oppressive that the local people rose in revolt in 864 and invited another Alid, Hasan ibn Zayd, to lead them.
Back in Samarra, the rest of the Turkic military establishment raised al-Mu'tazz to the throne, and under the command of the new caliph's brother, Abu Ahmad, marched on Baghdad.
The siege of Baghdad by the Samarran troops lasted for almost the entire year, and Muhammad ibn Abdallah led the defence in support of al-Musta'in.
He related hadiths, and was a patron of artists like the singer Ahmad ibn Yahya al-Makki, called Zunayn, who wrote his Kitab mujarrad fi'l-aghani ("Book of Choice Songs") for him.