Acalolepta australis is a species of flat-faced longhorn beetle belonging to the family Cerambycidae, subfamily Lamiinae.
Acalolepta australis is the largest species of the genus, reaching about 26- in length. The basic colour is blackish or reddish brown. Antennomeres I-III and the base of tibias show black spots.
Main host plants are Anisoptera polyandra, Araucaria cunninghamii, Hevea brasiliensis, Terminalia kaernbachii and Theobroma cacao.
This species can be found in northern Australia, Moluccas, New Ireland (island), New Britain and New Guinea.