The Koutoubia Mosque or Kutubiyya Mosque (Arabic: جامع الكتبية‎ Arabic pronunciation: [jaːmiʕu‿lkutubijːa(h)]) is the largest mosque in Marrakech, Morocco. The minaret was completed under the reign of the Almohad Caliph Yaqub al-Mansur (1184-1199) and was used as the model for the Giralda of Seville and for the Hassan Tower of Rabat.

The name is derived from the Arabic al-Koutoubiyyin, meaning "librarian", since it used to be surrounded by sellers of manuscripts. It is considered the ultimate structure of its kind. The tower is 69 m (221 ft) in height and has a lateral length of 12.8 m (41 ft). Six rooms (one above the other) constitute the interior; leading around them is a ramp by way of which the muezzin could ride up to the balcony. It is built in a traditional Almohad style and the tower is adorned with four copper globes.

According to legend, the globes were originally made of pure gold, and there were once supposed to have been only three globes. The fourth globe was donated by the wife of Yaqub el-Mansur as compensation for her failure to keep the fast for one day during the month of Ramadan. She had her golden jewelry melted down to form the fourth globe.