The neotropical genus Fosterella L.B. Smith (Pitcairnioideae, Bromeliaceae) comprises about 30 species, with a centre of diversity in semiarid to humid habitats of the Andean slopes and valleys of Bolivia. Morphologic differentiation of species is difficult because of a paucity of diagnostic characters, and little is known about the infrageneric phylogeny. Here, we present the results of an amplified fragment length polymorphism (AFLP) analysis of 77 Fosterella specimens, covering 18 recognized species and 9 as-yet undescribed morphospecies. Eight primer combinations produced 310 bands, which were scored as presence/absence characters. Neighbour-joining tree reconstruction revealed 12 clusters (A–L) with various levels of support. Well-supported species groups were also recovered by a principal coordinates analysis. With few exceptions, morphologically defined species boundaries were confirmed by the molecular data. Phylogenetic relationships between species groups remained ambiguous, however, because of short internal branch lengths. The AFLP data were complemented by a survey of the leaf anatomy of 19 Fosterella species. Species concepts and assemblages are discussed in the context of molecular, morphologic, anatomic, ecologic, and biogeographic data. The data suggest that accidental long-distance dispersal and founder events have been important for Fosterella speciation.