Old Mosque of Basra or Imam Ali Mosque is a historic mosque located in Basra, Iraq. It was founded in 635 AD during the era of the second Rashidun Caliph Umar ibn Al-Khattab. The mosque was later reconstructed during the era of the Umayyad Caliph Umar ibn Abd al-Aziz. It is the first mosque built in Basra, and among the oldest mosques in the history of Islam.