Seven species of corticolous and foliicolous lichens are recorded for the first time for Thailand. Four species are new to Asia: Acanthotrema brasilianum, Cruentotrema amazonum, Microtheliopsis uniseptata, and Ocellularia petrinensis. Asteristion cupulare is new to Southeast Asia, whereas Fellhanera semecarpi and Phylloblastia mucronata are new to Thailand. The genera Acanthotrema and Phylloblastia have not previously been reported from Thailand. The total number of lichen species known from Thailand is now 1,410. The main diagnostic characters and distributions of the new records are discussed and illustrations provided. Keywords: Ascomycota, diversity, South-east Asia, taxonomy, tropical biodiversity.