The scorpion fauna of the small Mona Island (= Isla de Mona), located roughly midway between Hispaniola and Puerto Rico and administratively belonging to the latter, is herein revised. Three species are confirmed to occur: the buthids Centruroides bani Armas et Marcano Fondeur, 1987 and Heteroctenus abudi (Armas et Marcano Fondeur, 1987), plus the diplocentrine scorpionid Cazierius garridoi Armas, 2005. The previously recorded Heteronebo sp. is reexamined and deemed a mislabeled specimen of Heteronebo portoricensis Francke, 1978 from adjacent Puerto Rico. Also, Centruroides mariaorum Santiago-Blay, 2009 is demonstrated to be a junior synonym of C. bani (implying the first demonstrable records of the latter from both Mona Island and Puerto Rico) and Rhopalurus virkkii Santiago-Blay, 2009 is confirmed as a junior synonym of H. abudi. A thorough photographic complement and supplementary ecological and distributional data are provided for every species.