The Siege of Shushtar was fought from 641 to 642 between the Sasanian Empire and the invading Arab Muslims of the Rashidun Caliphate. Shushtar was an ancient strong stronghold in Khuzestan, and was attacked by the Arabs under their commander Abu Musa Ashaari. Although the city managed to resist the Arabs, the Sasanians later faced desertion, which resulted in the Arabs capturing the city and capturing its commander, Hormuzan.