Hajeb El Ayoun (Arabic: حاجب العيون) is a town and commune in the Kairouan Governorate, Tunisia.

It is located at 35° 23′N, 9° 32′E and across fields from the west shores of Sidi Saad lake having the largest dam in Tunisia, which enables agricultural irrigation in the surrounding fields.

The town is also the seat in name at least of an ancient Christian titular Bishopric[5] In the 1830s the site was excavated by Lieutenant Harinezo,[6] who discovered the remains of a Christian era, basilica, with various inscriptions in situ.

The ruins have been suggested as the remains of the Roman civitas of Germaniciana.

The United States Army engaged Rommels Afrika Korps here on 19 February 1943.