The Al Abbas Mosque or Masjid al-Abbas is the mausoleum of Abbas ibn Ali, located across from the Imam Husayn (AS) Mosque in Karbala, Iraq.

Abbas was son of Ali ibn Abi Talib and the half-brother of Imam Hasan (AS) and Imam Husayn (AS), and was the flag-bearer for Imam Husayn (AS) in the Battle of Karbala. Also, he was the chief of the caravans of Imam Husayn (AS). The distance between the shrines of Abbas and Imam Husayn (AS) is the same as the distance between the hills of Al-Safa and Al-Marwah.

Millions of pilgrims visit the shrine and pay homage to it every year. The real grave of Abbas is beneath the masoulem, and is present in the shrine. Emperors and kings of various dynasties have offered valuable gifts and gems to the shrine of Abbas. It was designed by Persian and Central Asian architects. The central pear shaped dome is an ornately decorated structure. On its sides stand two tall minarets. The tomb is covered with pure gold and surrounded by a trellis of silver. Iranian carpets are rolled out on the floors.