We describe and illustrate a new species of Matelea Aubl. from Península de Nicoya, Costa Rica. Matelea nicoyana J. E. Jiménez, M. Méndez & J. A. Obregón is morphologically similar to M. pseudobarbata (Pittier) Woodson but is distinguished by its stems with dispersed, pilose trichomes, leaf blades without pilose trichomes and with 12 to 15 colleters, calyx lobes deltate, inflexed, and corolla with reflexed and contorted lobes covered by white-translucent, flexuous trichomes adaxially. Data on its distribution and habitat, phenology, conservation status, and morphologically related species are given and photographs are presented. A dichotomous key is presented for species from Costa Rica sharing similar indument. The species proposed here increases the number of Matelea species in Costa Rica to 17, nine of which are endemic.