Gadiforms and percopsiforms have historically been treated as prototypical or core paracanthopterygians. As such, they are the keys to unlocking the evolutionary history and limits of a revised Paracanthopterygii; therefore, we address the taxonomic compositions of gadiforms and percopsiforms and how they are related to each other and other putative basal acanthomorphs. We address these questions by first constructing a phylogenetic hypothesis based on multiple molecular sequences. Both maximum likelihood and parsimony criteria strongly support a Paracanthopterygii comprised of Percopsiformes + [Zeiformes + (Gadiformes + Stylephorus)]. Polymixiids are sister to this clade. Polymixiids + paracanthopterygians are in turn sister to the acanthopterygians (batrachoidiforms, beryciforms, lophiiforms, ophidioids, percomorphs) in the parsimony analysis but sister to Acanthopterygii + Lampriformes (minus Stylephorus) in the likelihood analysis. A review of published morphological characters, putatively pertinent to paracanthopterygian systematics were evaluated by the direct examination of specimens. Results find high congruence between the molecular tree and character-state distributions for many of these internal relationships. New interpretations of homologies of published characters are proposed based on topological and phylogenetic data.