A detailed revision of the genus Trematodon Michx. is given together with a key to species, illustrations and distribution maps for the five species of Trematodon now recognised in Australia. Of the nine species previously recorded for Australia, one species, T. amoenus (Müll.Hal.) I.G.Stone & G.A.M.Scott is endemic while T. flexipes Mitt., T. mackayi (R.Br.bis.) Broth. and T. suberectus Mitt., occur in Australia and New Zealand. Three species previously considered Australian endemics, T. baileyi Broth., T. brachyphyllus Müll.Hal. and T. longescens Müll. Hal., are now considered conspecific with the widespread T. longicollis Michaux, the type species for the genus.