The subgenus Laurentomantis in the genusGephyromantiscontains some of the least known amphibian species of Madagascar. The six currently valid nominal species are rainforest frogs known from few individuals, hampering a full understanding of the species diversity of the clade. We assembled data on specimens collected during field surveys over the past 30 years and integrated analysis of mitochondrial and nuclear-encoded genes of 88 individuals, a comprehensive bioacoustic analysis, and morphological comparisons to delimit a minimum of nine species-level lineages in the subgenus. To clarify the identity of the speciesGephyromantis malagasius, we applied a target-enrichment approach to a sample of the 110 year-old holotype ofMicrophryne malagasiaMethuen and Hewitt, 1913 to assign this specimen to a lineage based on a mitochondrial DNA barcode. The holotype clustered unambiguously with specimens previously namedG. ventrimaculatus. Consequently we propose to considerTrachymantis malagasia ventrimaculatusAngel, 1935 as a junior synonym ofGephyromantis malagasius. Due to this redefinition ofG. malagasius, no scientific name is available for any of the four deep lineages of frogs previously subsumed under this name, all characterized by red color ventrally on the hindlimbs. These are here formally named asGephyromantis fiharimpesp. nov.,G. matsilosp. nov.,G. oelkrugisp. nov., andG. portonaesp. nov.The new species are distinguishable from each other by genetic divergences of >4% uncorrected pairwise distance in a fragment of the 16S rRNA marker and a combination of morphological and bioacoustic characters.Gephyromantis fiharimpeandG. matsilooccur, respectively, at mid-elevations and lower elevations along a wide stretch of Madagascar’s eastern rainforest band, whileG. oelkrugiandG. portonaeappear to be more range-restricted in parts of Madagascar’s North East and Northern Central East regions. Open taxonomic questions surroundG. horridus, to which we here assign specimens from Montagne d’Ambre and the type locality Nosy Be; andG. ranjomavo, which contains genetically divergent populations from Marojejy, Tsaratanana, and Ampotsidy.