Acilius is a holarctic genus of diving beetles in the family Dytiscidae. It contains the following species:
Acilius abbreviatus Aubé, 1838Acilius athabascae Larson, 1975Acilius canaliculatus (Nicolai, 1822)Acilius confusus Bergsten, 2006Acilius duvergeri Gobert, 1874Acilius florissantensis Wickham, 1909Acilius fraternus (Harris, 1828)Acilius japonicus Brinck, 1939Acilius kishii Nakane, 1963Acilius mediatus (Say, 1823)Acilius oeningensis (Heer, 1847)Acilius praesulcatus Lomnicki, 1894Acilius semisulcatus Aubé, 1838Acilius sinensis Peschet, 1915Acilius sulcatus (Linnaeus, 1758)Acilius sylvanus Hilsenhoff, 1975
