The taxonomic revision of the Palaearctic beetle family Omalisidae is presented. The morphology of the family is described in detail and the relationships of genera are discussed. The genus Thilmanus Gemminger, 1869 is classified in Omalisidae and the subfamily Thilmaninae Kazantsev, 2005 described in Lycidae for Thilmanus is considered redundant in Omalisidae. The subgenus Phaeopterus Costa, 1857 is elevated to the genus level. Omalisus (Phaeopterus) minutus Pic, 1938 is proposed to be a junior subjective synonym of Phaeopterus unicolor Costa, 1857. Thilmanus longicollis var. laticeps Pic, 1913 from Southern France is elevated to the full species status, Thilmanus longicollis Pic, 1912 from Sardinia is proposed to be a junior subjective synonym of T. obscurus Baudi, 1872. Omalisus (Phaeopterus) nigricornis Reitter, 1881 is excluded from Omalisidae and placed in Euanoma Reitter, 1889 in Drilidae. Omalisus (Phaeopterus) flavangulus Späth, 1898 is proposed to be a junior subjective synonym of E. nigricornis Reitter, 1881. In total, eight species classified in three genera are recognized in Omalisidae. Redescriptions of all Omalisidae genera are provided. Each species of the family is presented with a diagnosis, full description, illustrations of male genitalia and a comprehensive bibliography. Extensive data on distribution of all species is provided and the distributions of genera and the species groups are discussed. A key to all Omalisidae species and genera is included and fully illustrated.