The Neotropical spider genus Neoxyphinus Birabén, 1953, is revised, comprising 10 species found from the West Indies to northern Argentina. The genus is characterized by a unique combination of characters, which include the presence of a set of low tubercles or large spikes on the posterior surface of carapace; male endites with an apical, retrolateral excavation bearing a subapical toothlike apophysis; palpal bulb strongly inflated; embolus compact, S-shaped, with large, round ejaculatory opening; epigynal atrium large, with angular lateral corners. The large, round ejaculatory duct may be a synapomorphy of the genus. The genus Hawkeswoodoonops Makhan and Ezzatpanah, 2011, is synonymized with Neoxyphinus and the two species included in that genus are considered as nomina dubia. The monotypic genus Decuana Dumitrescu and Georgescu, 1987, is also synonymized with Neoxyphinus and its type species, D. hispida Dumitrescu and Georgescu, 1987, is transferred to the genus and redescribed. Confirming a hypothesis raised in the literature, Dysderina termitophila Bristowe, 1938, is transferred to Neoxyphinus and recognized as the senior synonym of the type species N. ogloblini Birabén, 1953. Two other species are transferred from Dysderina to Neoxyphinus: D. keyserlingi Simon, 1907, here recognized as the senior synonym of D. rugosa Bristowe, 1938, and D. furtiva Chickering, 1968, of which the male is described for the first time. In addition to the redescription of N. termitophilus, n. comb., N. hispidus, n. comb., N. xyphinoides (Chamberlin and Ivie, 1942), N. keyserlingi, n. comb., and N. furtivus, n. comb., five new species are described: N. petrogoblin Abrahim and Ott, from the Amazon basin in Brazil, Colombia, Ecuador, and Peru; N. gregoblin Abrahim and Santos, from Venezuela; N. axe Abrahim and Brescovit, from Bahia, Brazil; N. boibumba Abrahim and Rheims, from Para, Brazil; and N. barreirosi Abrahim and Bonaldo, from Brazil, Colombia, Guyana, and Venezuela. With the exception of N. boibumba, known only from males, all new species are described from both sexes.