The phylogenetic relationships of Platycephalidae and its related taxa were analyzed. Platycephaloidei and Scorpaenoidei form a monophyletic group supported by two synapomorphies: presence of a backwardly-directed opercular spine and an extrinsic muscle derived from the hypaxial. Platycephaloidei and Plectrogenium, the triglids and peristediids are monophyletic, characterized by a posterior pelvic fossa. Bembradium and Plectrogenium constitute a monophyletic group, which divided initially from remainder of the clade. Next Parabembras, followed by Bembras, branched off the latter. Platycephalidae and its sister group, including the triglids, peristediids and hoplichthyids, have 4 synapomorphies. The triglids, peristediids and hoplichthyids share 15 apomorphies. The peristediids and hoplichthyids constitute a monophyletic group supported by 8 synapomorphies. The newly-defined suborder Platycephaloidei includes the following 7 families: Plectrogeniidae, Parabembridae, Bembridae, Triglidae, Peristediidae, Hoplichthyidae and Platycephalidae. Platycephalidae is redefined, being a monophyletic group supported by 6 synapomorphies, and including 2 subfamilies and 17 genera, 3 of them new.