A new microhylid frog is described from Bario, Kelabit Highlands of the State of Sarawak, in the Eastern Malaysia of Borneo Island. Morphologically, the new species differs from all known congeners in the combination of small body size; short fourth finger without subarticular tubercle; absence of subarticular tubercles on fifth toe, and usually on first finger; presence of light lateral stripe and dark inguinal spot; absence of nuptial pads and outer metatarsal tubercles. Acoustically, the new species differs from all congeners whose calls have been reported, except for K. baluensis and K. yongi, with short unpulsed notes emitted intermittently.