Lord Howe Island and associated island, Balls Pyramid, in the Tasman Sea between Australia and New Zealand, have a surprising diversity of terrestrial isopods. New species in the genera Pyrgoniscus, Cubaris and a new genus (Stigmops, n.gen.) of the family Armadillidae are described from Australian Museum collections made on Lord Howe Island. Two species, formerly placed in Anchicubaris, are moved to the new genus. Anchicubaris is revised to show how it differs from the new genus. With these changes, species of Anchicubaris no longer occur on Lord Howe Island. A lectotype for Anchicubaris fongosiensis is assigned. The homonymy of Cubaris granulatus Lewis, 1998b is resolved with a new name and a type species for the genus Sphenodillo Lewis, 1998b is assigned. A key to Lord Howe Armadillidae is provided. The biogeography of Armadillidae genera on Lord Howe Island shows possible links to neighbouring regions of New Caledonia and eastern Australia. Because relationships of species in the large genera Cubaris and Pyrgoniscus are unknown, precise area relationships cannot be estimated. The high diversity and presence of armadillids on the nearby rock, Balls Pyramid, suggests that the Lord Howe fauna is a contracted remnant of a much larger Pleistocene fauna, when lowered sea levels provided interconnections and much larger areas.