We introduce a new system of classification for the subfamily Scorpioninae Latreille, 1802 which includes genera Heterometrus Ehrenberg, 1828, Opistophthalmus C. L. Koch, 1837, Pandiborellius Rossi, 2015 stat. n., Pandinoides Fet, 1997, Pandinops Birula, 1913, Pandinurus Fet, 1997, Pandinus (Pandinus) Thorell, 1876, Pandinus (Pandinopsis) Vachon, 1974 stat. n., Pandinus (Pandipalpus) Rossi, 2015 stat. n., and Scorpio Linné, 1758. We provide a checklist of 41 valid species and their synonyms of Pandinus sensu lato. We revise Horn of Africa genera Pandiborellius stat. n. and Pandinurus; all species are fully complemented with color photos of live and preserved specimens, as well as their habitat. Included are morphological keys to the subfamily Scorpioninae and genera Pandiborellius stat. n. and Pandinurus. Several new characters in trichobothrial pattern, granulation of pedipalp movable and fixed fingers and spiniform formula of tarsomeres of legs are used and discussed. Described herein are Pandiborellius igdu sp. n. from Ethiopia, Pandiborellius insularis sp. n. from Eritrea, Pandinurus afar sp. n. from Ethiopia, and Pandinurus oromo sp. n. from Ethiopia. Pandinurus citernii (Borelli, 1919) comb. n. and Pandinurus intermedius (Borelli, 1919) comb. n. are restored from synonymy. Pandinurus (Pandipavesius) Rossi, 2015 is synonymized with Pandiborellius Rossi, 2015 stat. n.; Pandinus (Pandinoirens) Rossi, 2015 is synonymized with Pandinurus Fet, 1997; Pandinurus (Pandiborellius) sabbadinii Rossi, 2015 is synonymized with Pandiborellius magrettii (Borelli, 1901) comb. n.; Pandinurus (Pandinurus) cianferonii Rossi, 2015 is synonymized with Pandinurus pallidus (Kraepelin, 1894); Pandinus (Pandinoirens) riccardoi Rossi, 2015 and Pandinus (Pandinoirens) bottegoi Rossi, 2015 are synonymized with Pandinurus platycheles (Werner, 1916); Pandinus (Pandinurus) vachoni Rossi, 2014 is synonymized with Pandinurus sudanicus (Hirst, 1911); and Pandinurus (Pandipalpus) pygmaeus Rossi, 2015 is synonymized with Pandinus (Pandipalpus) lowei Kovařík, 2012 comb. n.. Hemispermatophores of Pandiborellius insularis sp. n., Pandinurus afar sp. n. and Pandinurus oromo sp. n are illustrated and described, and morphology of Pandinus sensu lato hemispermatophores is discussed.