Whether the languages of the Reefs-Santa Cruz (RSC) group have a Papuan or an Austronesian origin has long been in dispute. Various background issues are treated in the introductory section. In section 2 we examine the lexicon of the RSC and Utupua-Vanikoro languages and show that there are regular sound correspondences among these languages, and that RSC languages display regular reflexes of Proto-Oceanic etyma and are therefore Austronesian. We also show that together the RSC and Utupua-Vanikoro languages form an Oceanic subgroup, which we label "Temotu," and that the Temotu group is probably a first-order subgroup within the Oceanic family. In section 3, we examine a variety of constructions and morphemes in Äiwoo, the language of the Reef Islands, to see whether they have plausible Oceanic sources. The answer in most cases is that they do. This is important, as several of these constructions have in the past been given as evidence that the RSC languages have a Papuan origin. We conclude that the RSC languages are Austronesian and that there is no need to posit a Papuan element to explain their origin.