The pantropical genus Peperomia consists of approximately 1,600 species with highest diversity in the Neotropics, especially in the Andes of Peru. Our continuous field work in this country shows that a considerable amount of new species still await discovery. Following our studies of the tuberous species of Peperomia subgenus Tildenia from the Andes, Central America and Mexico, we now tackle the closely related clade of terrestrial succulent window-leaved Peperomia species. This group currently consists of 31 accepted taxa, and we here describe and illustrate 10 new species and one variety, entirely based on observations in the field and in our ex situ living collections. Distribution, habitat and phenology data as well as detailed comparisons with other species are also included.