Bab Agnaou (Arabic باب اكناو) is one of the nineteen gates of Marrakech, Morocco. It was built in the 12th century in the time of the Almohad dynasty.
The name Agnaou, like Gnaoua, in Berber refers to black people (cf. Akal-n-iguinawen - land of the black). The gate was called Bab al Kohl (also referring to black people) or Bab al Qsar (palace gate) in some historical sources.
The function of the gate must have been representation, first of all. The corner-pieces are decorated with floral decorations extending around a shell. This ornamentation is framed by three panels and on these panels is an inscription from the Quran in Maghribi, foliated Kufic letters, which were also used in Al-Andalus. Bab Agnaou was renovated and its opening reduced in size, during sultan Mohammed ben Abdallah. Forerunners of this horseshoe-shaped gate with its corner-pieces, framed by inscriptions from the Quran can be found in the Mezquita in Cordoba. It shows many similarities to the contemporary (much simpler) Bab Er-Rouah in Rabat.
Bab Agnaou gives entrance to the royal kasbah in the southern part of the medina of Marrakech. The kasbah, built by the Almohad sultan Yaqub al-Mansour, is the site of El Mansouria (the kasbah mosque), the El Badi Palace and the Saadian Tombs.