Hexarhopalus Fairmaire, 1891, a tenebrionid genus from Southeast Asia, is revised. The genus Leprocaulus Fairmaire, 1896 is transferred to Hexarhopalus and demoted to subgenus. The following 20 species are described as new: H. (Leprocaulus) jendeki sp. nov. from India; H. (L.) eva sp. nov., H. (L.) kubani sp. nov., H. (L.) lilligi sp. nov., H. (L.) pacholatkoi sp. nov., H. (s. str.) problematicus sp. nov. and H. (L.) seniori sp. nov. from Thailand; H. (L.) sinjaevi sp. nov. from Vietnam; H. (L.) cameroni sp. nov., H. (s. str.) loebli sp. nov. and H. (L.) merkli sp. nov. from West Malaysia; H. (L.) andoi sp. nov., H. (s. str.) bouchardi sp. nov., H. (s. str.) bremeri sp. nov., H. (L.) crockeri sp. nov., H. (L.) kaszabi sp. nov., H. (L.) masumotoi sp. nov. and H. (L.) tibangi sp. nov. from Borneo; H. (L.) schawalleri sp. nov. from Laos; and H.(L.) grimmi sp. nov. from Sumatra. The following synonyms are proposed (junior synonym first): Laosocryptobates Pic, 1928 and Apteroleprocaulus Kaszab, 1983 = Hexarhopalus Fairmaire, 1891; Pseudocoelophus Pic, 1922 = Leprocaulus Fairmaire, 1896; and Leprocaulus vietnamicus (Kaszab, 1980) = Hexarhopalus difformis (Pic, 1922). The following species are transferred or re-transferred from the genus Leprocaulus to the genus Hexarhopalus (Leprocaulus): Hexarhopalus montanus (Kaszab, 1982) comb. nov., H. difformis (Pic, 1922) comb. nov., H. borneensis (Kaszab, 1982) comb. nov., H. sumatranus (Kaszab, 1982) comb. nov., H. attenuatus (Pic, 1922) comb. nov., H. loeffleri (Kaszab, 1982) comb. nov., H. rotundicollis (Pic, 1922) comb. nov., H. punctithorax (Kaszab, 1982) comb. nov., H. particularis (Pic, 1922) comb. nov. and H. clavipes (Fairmaire, 1896) comb. nov. Derosphaerus granulipennis Blair, 1919 is transferred to the genus Hexarhopalus as H. granulipennis (Blair, 1919) comb. nov. The following species are transferred from the genus Hexarhopalus to the genus Misolampidius Solsky, 1875: Misolampidius foveipennis (Fairmaire, 1894) comb. nov., M. entomogonoides (Allard, 1896) comb. nov. and M. indicus (Allard, 1877) comb. nov. Distributions of and keys to Hexarhopalus species are presented. Taxonomy, relationships and ecology of this genus are discussed. Laosocryptobates tuberculatus