Recent phylogenetic studies on Nematinae based on DNA sequences have shown extensive incongruencies with current nomenclature of genus-group taxa. Here, we expand previous DNA sequence datasets based on three genes (CoI, Cytb, and EF-1α), to include a fourth (NaK) and more genera. The analyses largely confirm the previous findings, particularly the existence of two well-supported large clades, Euura and Pristiphora, together comprising more than 75% of the species of Nematinae. Basal relationships within these two clades remain poorly resolved, mirroring the difficulties in delimiting genera based on morphology. In addition, a moderately supported small clade, Nematus, is found. The relationships between the Euura, Pristiphora, and Nematus clades are uncertain. Therefore, to stabilize the nomenclature we treat these clades as genera. This taxonomic treatment results in numerous new combinations of species names. The following synonymies are proposed for the available genus-group names. Synonyms of Euura Newman, 1837: Cryptocampus Hartig, 1837, Euura Agassiz, 1848, Pontania Costa, 1852, syn. n., Epitactus Förster, 1854, syn. n., Amauronematus Konow, 1890, syn. n., Holcocneme Konow, 1890, syn. n., Pachynematus Konow, 1890, syn. n., Holcocnema Schulz, 1906, syn. n., Holcocnemis Konow, 1907, syn. n., Pteronidea Rohwer, 1911, syn. n., Pontopristia Malaise, 1921, syn. n., Brachycoluma Strand, 1929, syn. n., Decanematus Malaise, 1931, syn. n., Pikonema Ross, 1937, syn. n., Phyllocolpa Benson, 1960, syn. n., Eitelius Kontuniemi, 1966, syn. n., Gemmura E.L. Smith, 1968, Eupontania Zinovjev, 1985, syn. n., Larinematus Zhelochovtsev, 1988, syn. n., Polynematus Zhelochovtsev, 1988, syn. n., Bacconematus Zhelochovtsev, 1988, syn. n., Alpinematus Lacourt, 1996, syn. n., Epicenematus Lacourt, 1998, syn. n., Kontuniemiana Lacourt, 1998, syn. n., Lindqvistia Lacourt, 1998, syn. n., Luea Wei and Nie, 1998, syn. n., and Tubpontania Vikberg, 2010, syn. n. Synonyms of Nematus Panzer, 1801: Craesus Leach, 1817, Hypolaepus W.F. Kirby, 1882, and Paranematus Zinovjev, 1978. Synonyms of Pristiphora Latreille, 1810: Diphadnus Hartig, 1837, Lygaeonematus Konow, 1890, Micronematus Konow, 1890, Gymnonychus Marlatt, 1896, Neopareophora MacGillivray, 1908, syn. n., Neotomostethus MacGillivray, 1908, Dineuridea Rohwer, 1912, Sala Ross, 1937, Pristola Ross, 1945, syn. n., Nepionema Benson, 1960, syn. n., Melastola Wong, 1968, syn. n., Sharliphora Wong, 1969, Oligonematus Zhelochovtsev, 1988, Lygaeotus Liston, 1993, Lygaeophora Liston, 1993, and Pristicampus Zinovjev, 1993, syn. n. Varna Ross, 1937, syn. n. is treated as a synonym of Dineura Dahlbom 1835. Stauronematus Benson, 1953 is treated as a separate genus from Pristiphora. Names of 20 species-group taxa are junior secondary homonyms when combined with Euura. Replacement names are proposed for these. To facilitate the identification of Nematinae genera, we provide an illustrated key to the 31 extant genera of world Nematinae.