An understanding of fishing gear selectivity is crucial for managing fisheries appropriately. This study examined the gill net selectivity of four teleost species that are recreationally and/or commercially fished with gill nets in south-western Australia; Black Bream (Acanthopagrus butcheri), Sea Mullet (Mugil cephalus), Perth Herring (Nematalosa vlaminghi)and Tailor (Pomatomus saltatrix). Sampling was undertaken in five south-western Australian estuaries using gill nets with mesh sizes ranging from 38 to 127 mm. The total length of all four species increased with increasing mesh size. Linear relationships between maximum girth (G_max) and opercular girth (G_ope), and total length (TL) varied markedly among species. Selectivity curves, i.e. the relative retention probability of a fish at a given length within a mesh, were estimated using the SELECT method. The spread and mode of these curves varied extensively among species due to their morphological and behavioural characteristics. Modes for the selectivity curves of A. butcheri, the species with the greatest girth at any given length, were less than those of the other three species across all mesh sizes. The selectivity curves were broadest for P. saltatrix due to the far greater proportion of tangled fish than meshed fish, i.e. gilled and wedged. The gill net selectivity of A. butcheri differed among estuaries, which reflects significant differences (ANCOVA, P <0.01) in body condition, and thus girth-length relationships, of fish among the five estuaries. These results have the scope for use by fisheries managers in determining the most suitable mesh size regulations for estuarine gill net fisheries.