The Imam Ali Mosque, also known as Meshed Ali or the Tomb of Ali, is a mosque located in Najaf, Iraq. It is venerated as a holy site by Muslims, particularly Shiites, most of whom believe that Imam Ali ibn Abi Talib, the son-in-law of the Prophet Muhammad and the fourth caliph, is buried there. Because Ali was also Muhammad's cousin, he is considered by Shiite tradition to be the first legitimate caliph, and the first Imam.

The mosque was first built by the Iranian ruler the Daylamite Fannakhosraw Azod ad Dowleh in 977 over the tomb of Ali. After being destroyed by fire, it was rebuilt by the Seljuk Malik Shah I in 1086, and rebuilt yet again by the Safavid Shah Ismail I shortly after 1500.

The shrine is venerated as the fourth holiest site by Muslims, particularly Shias, and Shia Imam Ali ibn Abi Talib, the son-in-law of the Prophet Muhammad and the fourth caliph, is buried there. The Imam Ali Shrine is the third holiest site (see below) for the estimated 400 million followers of the Shia branch of Islam worldwide – approximately 20 percent of total Muslims. It is estimated that only Mecca and Medina receive more Muslim pilgrims.