Tatbir (Arabic: تطبير, romanized: Taṭbīr) is a form of self-flagellation rituals practiced by some Shia Muslims in commemoration of the killing of Husayn ibn Ali and his partisans in the Battle of Karbala by forces of the second Umayyad caliph Yazid I (r. 680–683).
The ritual is practiced in the Islamic month of Muharram, usually on Ashura. Tatbir involves striking oneself with chains or swords. It has been considered haram ("forbidden") by most of the Shia clergy, who cite it as self-harm.