The Serranidae is a large and diverse family of marine fishes that is the subject of extensive phylogenetic contention. Recent molecular studies have supported a monophyletic Serranidae, but only by excluding certain problematic genera. One of these genera, Acanthistius, is particularly problematic and has been regarded as incertae sedis, partly due to poor taxon sampling. The genus, with 11 species, is exclusively distributed in the Southern Hemisphere, with Australia and New Zealand accounting for nearly half of the global diversity. Some species are rare, with most available specimens being formalin fixed, whereas other species have contentious identities and potentially require taxonomic revisions themselves. We sequenced multiple mitochondrial and nuclear markers from eight of eleven species of Acanthistius to produce a robust estimate of the evolutionary relationships within the genus. Building on this improved taxon sampling, we inferred the phylogenetic placement of the genus Acanthistius in relation to Serranidae. Our results provide new insights into the interspecific relationships within Acanthistius and provide a foundation for future, large-scale phylogenetic studies to resolve the historically problematic monophyly of Serranidae.