Abstract <p>Migrations, dispersal, and the conditions and sequence of speciation in righteye flounders of the subfamily Hippoglossoidinae are analyzed using the method of historical biogeography. It is shown that the morpho-ecological evolution of the group was directed by adaptation to progressive climate cooling and that the species divergence occurred during the isolation of the Arctic Basin and the Sea of Japan in the Plio-Pleistocene. As a result of the analysis of the origin and dispersal of righteye flounders, the validity of the species <i>Hippoglossoides robustus</i> and <i>H. herzensteini</i> is recognized, as well as the division of the genus <i>Hippoglossoides</i> into the subgenera <i>Hippoglossoides</i> and <i>Cleisthenes</i>.</p>