The Gaoligong Mountain Range in Yunnan Province, China, is characterized by its large variation in elevation and topography, together with its wide latitudinal range, resulting in extremely high levels of biodiversity. Studies show that the amphibian diversity of the Gaoligong Mountain Range is largely underestimated, especially in the south. During herpetological surveys in 2023 and 2024, three specimens of Leptobrachella were collected from the mountain at Tongbiguan Provincial Nature Reserve. Subsequent morphological comparisons and a phylogenetic reconstruction revealed that these specimens belonged to a previously unknown and morphologically distinct lineage of Leptobrachella, which we formally describe. Our discovery brings the number of species in the genus to 108, 44 of which occur in China, and seven on Gaoligong Mountain Range. This result confirms the underestimated amphibian diversity of the Gaoligong Mountain Range, especially in Tongbiguan Provincial Nature Reserve, where multiple sympatric congeneric species occur, including four species of Leptobrachella, five species and a putative new species of Xenophrys, and three species of Polypedates. These findings also highlight the need for future research to investigate the mechanisms of sympatric and syntopic coexistence.