Seifallah Ben Omar Ben Mohamed Ben Hassine (Arabic: سيف الله بن عمر بن محمد بن حسين, romanized: Sayf Allāh ibn ‘Umar ibn Muhammad ibn Ḥusayn), known as Abu Ayyad al-Tunisi (Arabic: أبو عياض التونسي, romanized: ’Abū ‘Iyāḍ at-Tunūsī), was a Tunisian Islamic militant and the founder and leader of Ansar al-Sharia (Tunisia).