Al-Kabir Mosque, also known as the Great Mosque of Algiers or El-Djamaa El-Kebir, is a historic mosque in Algiers, Algeria. It is one of the few remaining examples of Almoravid architecture. It is the oldest mosque in Algiers and is said to be the oldest mosque in Algeria after Sidi Okba Mosque. It was built in 1097 under sultan Ali ibn Yusuf.

The Mosque with its naves perpendicular to the qibla wall and its rectangular courtyard bordered on both its narrower sides by a riwaq (gallery) was destined to become a model of religious architecture. The main body of the building, with its rectangular layout, is wider than it is deep. The minaret, of later construction in 1332, rises up from the north-western corner. The riwaq at the outside of the mosque was built in 1840. Its construction was a consequence of a complete reconstruction of the street by the French.

Two door openings that led to two small, oblong chambers are adjacent to the mihrab on either side. One of these rooms used to hold the minbar, which was moved on rails to the prayer hall so the Imam could offer the daily prayers and deliver sermons. The minbar itself is now conserved in the National Museum of Antiquities and Islamic Arts in Algiers, but the rails that were formerly used to move it are still buried in the floor.

The prayer hall can be located beneath the first five of the mosque’s nine bays, which run parallel to the qibla wall and measure roughly 38 by 46 meters. The mosque is laid out in a 9 by 11 grid. The exterior bays of the building encompass the courtyard. Although its center aisle is bigger than the rest, as an early Almoravid structure, it does not yet completely exhibit the distinctive T-shaped design typical of later Almoravid mosques.

The prayer hall is divided into eleven aisles that run parallel to the southern qibla wall and are connected by rows of horseshoe arches that are supported by masonry pillars that have been painted white. The fact that the central aisle is broader than the rest suggests a T-plan arrangement, which would eventually become the norm for mosque building in the Maghreb. In the mosque’s northern section, there is a rectangular courtyard that is about 11 by 21 meters in size and is enclosed by arcades.

The 1097 construction of the mosque included the mihrab, which was damaged by French assault in the 17th century. The reconstructed mihrab features recessed lobed arches at the end of the central, considerably wider nave, which is a characteristic design used in Algiers in the 18th century. A plain fresco façade flanked on either side by two tiny spiral columns and an ogive stucco arch that can be seen in relief. A flat floored niche holds the mihrab.