Al-Muhtadi (Arabic: المهتدي‎) (died June 870) was the Abbasid Caliph in Baghdad from 869 to 870.

After the death of al-Mu'tazz, the Turks chose his cousin, al-Muhtadi, son of al-Wathiq by a Grecian slave-girl, as the new Caliph. Al-Muhtadi turned out be firm and virtuous compared to the last few Caliphs. If he had come earlier, he might have restored life to the Caliphate; however, by now the Turks held more power.

Under him, the Court soon saw a transformation. Singing girls and musicians were expelled; justice was done daily in open court; wine and games were prohibited. He set Umar ibn Abd al-Aziz, the Umayyad Caliph, as his model and exemplar.

His reign, however, lasted less than a year. After some disagreements and conspiracies, he was killed by the Turks in 256 AH (June 870); he was thirty-eight then. The early Arab writers praise his justice and piety; and had he not been killed so soon, he could have been placed among the best of Abbasid Caliphs.