The genus Nanotopsis Schuster is revised. The two species currently included in the genus, Nanotopsis isolatrix Schuster, male, and N. malincha (Casal), female, are redescribed, and four new species are described: Nanotopsis delsinnei, male and female, from Paraguay and Argentina; N. leleji, male, from Argentina; N. paglianoi, male, from Guatemala; and N. panamae, male and female, from Panama. Additional records for N. isolatrix and N. malincha are given. Body and genitalia of males are illustrated for the first time. A key is provided for the six species of the genus Nanotopsis, species that have disjunct distributions in America: Guatemala, Panama, Brazil, Paraguay, and Argentina.