This note describes a case of beak deformity in a specimen of Monteiro's hornbill (Tockus monteiri Hartlaub, 1865) observed in north-central Namibia. The deformity consisted of an elongated upper mandible. Although this teratology presumably makes it more difficult to find food and maintain its feathers, the observed bird had reached adult size and appeared to be healthy. Keywords: Avian keratin disorder, beak abnormality, elongated beak, Monteiro's hornbill, Namibia, rhamphotheca.