The 35 species of the genus Tachyporus Gravenhorst (Staphylindae: Tachyporinae) of North and Central America are revised. Eighteen new species are described: neomexicanus, fenyesi, and howdenorum from the southwestern United States; sharpi from Mexico and the western United States; blomae from Mexico; nigripennis from California; dimorphus, pacificus, and stacesmithi from the Pacific northwest; rulomoides and browni from southeastern Canada and the northeastern United States; and borealis, canadensis, nimbicola, inornatus, ornatus, lecontei, and flavipennis, which are transcontinental in the United States and Canada. Two European species are reported for the first time from North America: abdominalis (Fabricius) and transversalis Gravenhorst. The following new specific synonymy is proposed: tehamae Blackwelder (= californicus Horn); temacus Blackwelder, oregonus Blackwelder, and alleni Blackwelder (= mexicanus Sharp); and acaudus Say, maculipennis LeConte, and chrysomelinus var. infuscatus Bernhauer (= jocosus Say). The genus is divided into 2 subgenera of which Palporus (type species Staphylinus nitidulus Fabricius) is described as new. The subgenus Tachyporus is divided into 12 species groups. Each species is described and its distribution is mapped. The male aedeagus and the pattern of elytral chaetotaxy are illustrated for each species. Major generic characters are illustrated with the aid of scanning electron photomicrographs. Neotypes are designated for the Say species faber, jocosus, and acaudus and lectotypes are designated (when needed) for the North and Central American species described by Erichson, LeConte, Horn, Sharp, and Blatchley and for a variety described by Bernhauer. A diagnostic key for all the species is given.