Incilius guanacaste is a species of toad in the family Bufonidae. It is endemic to the Cordillera de Guanacaste in northern Costa Rica. The species is only known from the slopes of Miravalles Volcano and Rincón de la Vieja Volcano. Its natural habitats are cloud forests and wind-swept elfin forests, presumably in association with deep leaf litter. The known range of this little-known species is fully within protected areas.