The Potamophylax winneguthi species cluster comprises species with limited distribution, currently documented from Kosovo, Serbia, Bosnia and Herzegovina and Bulgaria. In this paper, we describe a new species, Potamophylax kosovaensis sp. nov., discovered in two tributaries of the Ibër River Basin, within the Kopaonik Mountains of the Republic of Kosovo. Morphologically, males of this species closely resemble those of P. idliri Ibrahimi, Bilalli & Kučinić, 2022 from Serbia's Jastrebac Mountain and P. humoinsapiens Ibrahimi & Bilalli, 2023 from the Sharr Mountains in the Republic of Kosovo. However, the new species can be distinguished by its smaller aedeagus, thicker and differently-shaped parameres, as well as distinctive patterns and elongated spines on the parameres. Notably, this species is restricted to spring areas, indicating sensitivity to water pollution and habitat degradation. Additionally, we provide a list of caddisfly species found in sympatry with the new species. Potamophylax kosovaensis sp. nov. is the third known species within the Potamophylax winneguthi species cluster, identified in the Republic of Kosovo.