The amphipod (Crustacea) family Stegocephalidae Dana, 1852 is revised, and the results of a phylogenetic analysis of the family are presented. The morphological information, obtained mainly through direct examination of the species, has been transformed into 200 characters. 91 stegocephalid species (91% of all recognized species) are included in the analysis, in addition to six outgroup taxa. Based upon this analysis, the family is divided into five subfamilies and 26 genera. Four new subfamilies (Andaniexinae, Andaniopsinae, Bathystegocephalinae & Parandaniinae) and ten new genera (Alania, Austrocephaloides, Austrophippsia, Bouscephalus, Gordania, Medi-terexis, Pseudo, Schellenbergia, Stegonomadia & Stegomorphia) are erected. Five genera are put into synonymy (Andaniella with Andaniopsis; Phippsiella and Stegocephalopsis with Stegocephalus; Stegophippsiella with Stego-cephalina; Euandania with Parandania).