The Asian bagrid catfish genus Hemibagrus is revised. Eight species groups (H. baramensis, H. guttatus, H. menoda, H. nemurus, H. olyroides, H. planiceps, H. pluriradiatus, and H. wyckii species groups) are recognised, some of which may be natural. They can be diagnosed chiefly by a combination of characters: vertebral number, length of the adipose-fin base, and colouration. The identification of Hemibagrus species is difficult mainly because of the lack of well-defined characters and considerable plasticity in measurements commonly used for diagnosing species in other catfish groups. In this study, other taxonomic characters have been investigated to determine their usefulness in differentiating the species. It was found that morphological characters associated with the adipose fin (length of adipose-fin base, dorsal to adipose distance, and shape of adipose fin), head (shape of snout and head width relative to its length), and eye (eye diameter and interorbital distance) are characters useful in species differentiation. Thirty-two valid species are recognised in this study, of which three are described as new, viz. H. divaricatus from western Peninsular Malaysia, H. lacustrinus from Danau Singkarak and its associated drainages in western Sumatra, and H. semotus from northeastern Borneo.