We present a checklist of 26 ant species found in Mauritania, based on published, unpublished, and new records. There are published records of only 15 ant species from Mauritania, almost all based on specimens collected during a 1908 expedition. In September 2022, we surveyed ants for three days in the Dakhlet Nouadhibou Region of northwestern Mauritania. We collected 13 ant species, including 11 with no previously published records from Mauritania: Cardiocondyla emeryi Forel, 1881, Cardiocondyla mauritanica Forel, 1890, Cardiocondyla nigra Forel, 1905, Hypoponera punctatissima (Roger, 1859), Lepisiota canescens (Emery, 1897), Messor foreli Santschi, 1923, Monomorium salomonis (Linnaeus, 1758), Paratrechina longicornis (Latreille, 1802), Pheidole indica Mayr, 1879, Pheidole megacephala (Fabricius, 1793), and Tetraponera ambigua (Emery, 1895). Our checklist remains woefully incomplete; e.g., neighboring countries of Morocco and Algeria each have more than 200 known ant species.