A new species of squeaker frog (genus Arthroleptis) is described from the northern mountains of the Cameroon Volcanic Line, a species-rich region within the West African biodiversity hotspot. This new species is associated with human-altered landscapes, including farms and grasslands, and is known from the highland areas near Bamenda, including Mt. Oku, Cameroon, as well as the Obudu and Mambilla Plateaus of eastern Nigeria. The known distribution suggests that it may eventually also be found throughout the Acha-Tugi Ridge that traverses the Cameroon–Nigeria border. More than 40 years ago, a specimen from one of these populations was recognized as probably representing a new species, but no further work was published on this material. We posit that the taxonomy of this new species has proven problematic because of morphological similarity to Arthroleptis poecilonotus. Although in some ways resembling A. poecilonotus, a molecular phylogeny based on mitochondrial gene sequence data demonstrates that the new species is not closely related to A. poecilonotus and, instead, forms a clade with A. krokosua, A. perreti, and A. variabilis. The new species is diagnosable by the combination of medium–small body size (24–29 mm snout–vent length in adult females), the color patterns of the venter and head, and a relatively stout hindlimb with a prominent inner metatarsal tubercle. The description of this new species further highlights these mountains as an important region of endemism within the Cameroon Volcanic Line.