The Battle of Dayr al-Aqul was fought on April 8, 876, between forces of the Saffarid ruler Ya'qub ibn Laith and the Abbasid Caliphate. Taking place some 80 km southeast (downstream) of Baghdad, the battle ended in a decisive victory for the Abbasids, forcing Ya'qub to halt his advance into Iraq.

The town of Dayr al-ʿĀqūl (Arabic: دير العاقول, Persian: دیرالعاقول; literally "monastery at the river-bend", from a Syriac ʿaqūlā "bend") was the main town of the fertile district (ṭassūj) in central Nahrawan, making it the most important town on the Tigris between Baghdad and Wasit. The battle itself took place near a village of the town's district, called Istarband, between Dayr al-Aqul itself and Sib Bani Kuma.