Lachnomyrmex is a Neotropical genus of ants in the subfamily Myrmicinae. The genus consists of 16 species restricted to the Neotropics, known from southern Mexico to northern Argentina (and Trinidad just off the coast of Venezuela). They are most often found in the leaf litter of wet forests, with nests located on the ground. Workers forage alone, apparently without recruiting nestmates or using pheromones. Within the tribe Stenammini, they seem to be most closely related to the genera Lordomyrma of Indo-Australia and Cyphoidris of Africa.