Eight species of the lichen genus Pertusaria (Pertusariaceae) are reported from the Juan Fernández Archipelago (Chile). Pertusaria fernandeziana is described as a new species and two species, Pertusaria phlyctaenula Nyl. and Pertusaria dehiscens Müll. Arg., are recorded for the first time from the archipelago. Range extensions of the known distribution within the archipelago are reported for Pertusaria hadrocarpa Zahlbr., Pertusaria melanospora Nyl., Pertusaria pachythallina (Räsänen) Messuti, Pertusaria papillulata Nyl., and Pertusaria velata (Turner) Nyl. Pertusaria polycarpa Kremp. var. monospora Zahlbr. is reduced to synonymy with Pertusaria papillulata and Pertusaria chilena Zahlbr. is synonymized with Pertusaria velata. A diagnostic key, descriptions, and illustrations of the species are presented with data on their habitat ecology and distribution.