Bab Guissa Mosque is a medieval mosque located in northern Fes el-Bali, the old city of Fez, Morocco. According to an inscription on one of its marble columns, the mosque was built in the 14th century AD, during the reign of the Marinid sultan Abu al-Hasan. The mosque of Bab Guissa was inscribed as a UNESCO World Heritage Site in 1981 as part of Medina of Fez.