This paper presents a revision of the lichen genus Ramalina in Australia. Of the 60 Ramalina taxa previously listed for Australia in catalogues only nine of those names are retained, six with unchanged status. Twenty-eight taxa belonging to 20 species are recognized for Australia. Two are new species: R. filicaulis and R. tropica. A new variety R. subfraxinea var. norstictica and a new subspecies R. inflata subsp. australis are described, and four names, R. celastri subsp. ovalis, R. inflata subsp. perpusilia, R. subfraxinea var. confirmata, and R. subfraxinea var. leiodea are new combinations. The taxonomically important features of this genus (viz. morphology, anatomy, and chemistry) are discussed. In delimiting taxa, the morphological plasticity shown by this genus has been taken into consideration so that a wide range in infraspecific variation has been accepted for some of the taxa. The distribution patterns of the Australian Ramalinae are shown to closely follow the distribution of Australian phanerogam groups, which are controlled by the environmental parameters of rainfall and temperature; this enables the Ramalinae to be conveniently divided into three response groups (viz. megatherm, mesotherm, and microtherm) as used to divide the Australian phanerogams. On the basis of species diversity it is hypothesised that the genus had its origin in west Gondwanaland (South America and Africa) and then spread to the east. It is suggested that subsequent speciation occurred within Australia.