Al-Afdal Shahanshah (died 1121) was a vizier of the Fatimid caliphs.

He was the son of Badr al-Jamali, an Armenian Mamluk. Badr was vizier for the Fatimids in Cairo from 1074 until his death in 1094, when al-Afdal succeeded him. Caliph Ma'ad al-Mustansir Billah died soon afterwards, and al-Afdal appointed al-Musta'li, a child, caliph, instead of al-Mustali's much older brother Nizar, who had been designated successor. Nizar revolted and was defeated; his supporters, led by Hassan-i-Sabah, fled west, where Hassan established the Hashshashin (Assassins).

At this time Fatimid power in Palestine had been reduced by the arrival of the Seljuk Turks. In 1098 al-Afdal recaptured Jerusalem from the Seljuks, and expelled its Ortoqid governors in place of a Fatimid. The next year, Jerusalem was captured by crusaders; al-Afdal was at first unconcerned with them, assuming they were Byzantine mercenaries and would be content with the capture of Antioch from the Seljuk Turks, also enemies of the Fatimids. When it became apparent that the crusaders would not rest until they had control of the city, al-Afdal marched out from Cairo, but was too late to rescue Jerusalem, which fell on July 15, 1099. On August 12, the crusaders surprised al-Afdal at the Battle of Ascalon and completely defeated him. Al-Afdal marched out every year to attack the newfound Kingdom of Jerusalem, and in 1105 attempted to ally with Damascus agaist them, but was defeated at Ramla. The crusaders remained in the city until the arrival of Saladin decades later.

Al-Afdal also introduced tax (iqta) reform in Egypt, which remained in place until Saladin took over Egypt. Al-Afdal was nicknamed Jalal al-Islam ("glory of Islam") and Nasir al-Din ("Protector of the Faith"). He was assassinated in 1121 and succeeded by Al-Bata'ihi.