Questions have been raised about the precise genetic affiliation of the Enggano language of the Barrier Islands, Sumatra. Such questions have been largely based on Enggano’s lexicon, which shows little trace of an Austronesian heritage. In this paper, I examine a wider range of evidence and show that Enggano is clearly an Austronesian language of the Malayo-Polynesian (MP) subgroup. This is achieved through the establishment of regular sound correspondences between Enggano and Proto–Malayo-Polynesian reconstructions in both the bound morphology and lexicon. I conclude by examining the possible relations of Enggano within MP and show that there is no good evidence of innovations shared between Enggano and any other MP language or subgroup. In the absence of such shared innovations, Enggano should be considered one of several primary branches of MP.