Abstract The marine isopod family Serolidae is reviewed for the oceanic regions of the tropical and subtropical southwestern Pacific, namely from off Lord Howe Island, Norfolk Island, northern Coral Sea, New Caledonia and Fiji. Two new genera are established: Sedorolis gen. n., monotypic, from New Caledonia and Myopiarolis gen. n., a widespread Southern Hemisphere genus with 11 (eight described) species. The following new species are described: Heteroserolis pellucida (New Caledonia), Sedorolis simplex (New Caledonia), Myopiarolis koro (Fiji), M. systir (New Caledonia), M. norfanz (Lord Howe Plateau and off Norfolk Island), M. lippa (northern Coral Sea), and Thysanoserolis orbicula (New Caledonia). Keys are provided to the serolid genera and the species of Myopiarolis from the southwestern Pacific. The genus Caecoserolis Wägele, 1994 is redefined and restricted to the type species.