The Great Mosque of Djenne represent the Sudano-Sahelian architecture. The mosque has the shape of a square of 75 meters on each side and pyramidal. Its height is 20 meters. The roof is supported by 90 pillars and has 104 ventilation holes. It can hold a thousand people.

The prayer wall or qibla faces east in the direction of Mecca; it overlooks the market place of Djenné. This wall is dominated by three large rectangular-shaped minarets that protrude, as do the eighteen buttresses. Each of the minarets contains a spiral staircase leading to the summit platform. The top of each tower ends in a cone topped with an ostrich egg.

The walls are 40 to 20 cm thick; this depends on their height, the tallest are the thickest, their base must indeed be proportional to their weight. They are made of raw earth bricks, called ferey, jointed with mortar and coated with a layer of plaster, both of the same composition. This plaster gives the building its gently rounded shapes. Bundles of palm branches are driven into the depth of the walls to absorb the cracks that come from the varying stresses of temperature and humidity changes. They give the building a really characteristic spiky look. The mud walls insulate the interior of the building from the strongest heat during the day, ensuring thermal regulation with the cooler nights. Earthen pipe gutters overflow the edge of the roof and channel rainwater away from the walls.