Previous Australian records of Ascothoracida are summarised. In the Synagogidae, three new species of Gorgonolaureus Utinomi are described from primnoid (Pterostenella plumatilis (Rousseau)), paramuriceid (unidentified), and gorgoniid (Eunicella sp.) gorgonacean hosts off Western Australia, Vietnam, and New Caledonia, respectively. The first two species are from unusually shallow depths, 80 to 100 m, the third from bathyal depths. Flatsia n.gen., with one species from 73 to 82 m depth off New South Wales, host unknown, is provisionally assigned to the Synagogidae. In the Lauridae, two new species of (Baccalaureus Broch are described from the subtidal zoanthid Isaurus tuberculatus Gray on the Great Barrier Reef and the solitary zoanthid Sphenopus marsupialis Steenstrup at several shallow sites (40-86 m) off Queensland and Western Australia and in the Andaman Sea. In the Petrarcidae, morphological and ecological notes on Petrarca okadai Grygier infesting the coral Heteropsammia cochlea (Spengler) at Lizard Island, Queensland, are presented. Two new species of Petrarca Fowler are described infesting the solitary coral Fungiacyathus sp. off Moreton Bay, Queensland, and the hermatypic reef coral Turbinaria reniformis Bernard at Lizard Island. An unnamed species of Petrarca from the solitary coral (Anthemiphyllia dentata Alcock collected between 110 and 350 m off Queensland is partly described. A list and some photographs of other new records of galls caused by petrarcid ascothoracidans in various Indo-Pacific scleractinians, especially Turbinaria spp. and other dendrophylliids, are presented.