Abū ʿAlī al-Ḥasan al-Aʿsam ibn Aḥmad ibn al-Ḥasan ibn Bahrām al-Jannābī (Arabic: أَبُو عَلِيّ ٱلحَسَن ٱلأَعْصَم بْنُ أَحْمَد بْنِ ٱلحَسَن بْنِ بَهْرَام الجَنَّابِيّ; al-Ahsa Oasis, 891 – Ramla, 977), was a Qarmatian leader, chiefly known as the military commander of the Qarmatian invasions of Syria (especially around Damascus and Palestine) in 968–977. Already in 968, he led attacks on the Ikhshidids, capturing Damascus and Ramla and extracting pledges of tribute. Following the Fatimid conquest of Egypt and the overthrow of the Ikhshidids, in 971–974 al-A'sam led attacks against the Fatimid Caliphate, who began to expand into Syria. The Qarmatians repeatedly evicted the Fatimids from Syria and invaded Egypt itself twice, in 971 and 974, before being defeated at the gates of Cairo and driven back. Al-A'sam continued fighting against the Fatimids, now alongside the Turkish general Alptakin, until his death in March 977. In the next year, the Fatimids managed to overcome the allies, and concluded a treaty with the Qarmatians that signalled the end of their invasions of Syria.