This paper is the first study of melitid amphipods from tropical Australia. Seventeen species of Melitidae in the genera Ceradocus, Dulichiella, Elasmopus, Maera, Mallacoota and Parelasmopus are recorded from Lizard Island and adjacent reefs. In addition Ceradocus hawaiensis Barnard is recorded from Heron Island. Seven new species are described: Ceradocus oxyodus, C. wooree, C. yandala, Elasmopus crenulatus, E. spinicarpus, Maera griffini and Mallacoota balara. A lectotype is established and described for Parelasmopus suensis. The diagnosis for the genus Mallacoota is expanded and a key to the known species included.
None of the Melitidae from Lizard Island and adjacent reefs has been recorded from southern or south-eastern Australia. Madagascar and Mauritius have the highest number of melitid species in common with the Lizard Island area.