Forty-five lichen species are reported from Aldabra, an atoll of four main islands and numerous islets located in the Indian Ocean. Thirty-three species are new to Aldabra. The lichen flora is characteristic of the Indian Ocean islands. It is dominated by pantropical species, showing a rather weak statistical correlation (Sørensson Coefficient) of 22.0 between Aldabra and the islands of the granitic Seychelles and a surprisingly higher correlation of 36.5 with the Chagos Archipelago more than five times the distance away.