This thesis discusses topics in the grammar of Lelepa, an Oceanic language spoken by about 500 people on the islands of Lelepa and Efate in the centre of the Vanuatu archipelago. The areas of grammar covered in the thesis are phonology (chapter 2), morphology (chapter 3), word classes (chapter 4), noun phrases (chapter 5), possession (chapter 6), clause structure and grammatical relations (chapter 7), verb classes and valency changing devices (chapter 8), the verb complex (chapter 9), complex predicates (chapter 10), aspect and modality (chapter 11), coordination and subordination (chapter 12). The phonemic inventory is of medium to small size, with fourteen consonants and five vowels. It includes two typologically rare labial-velar consonants. Stress is not phonemic. Syllables can be complex and consonant clusters are allowed in onset and coda positions. The most important phonological process is vowel reduction, which represent a significant driver of language change. Clausal word order is SVO. Oblique arguments follow the object(s), and adjuncts occur in initial or final position in the clause. An exception is the benefactive phrase, an adjunct encoding beneficiaries which occurs between the subject proclitic and the verb, and makes the verb complex a discontinuous structure. The benefactive phrase is cross-linguistically unusual and makes central Vanuatu languages distinctive. Of typological interest is the split dividing objects along two classes of transitive verbs. It has its source in a semantic distinction between significantly affected Ps and less affected Ps. However, the split is lexical because borrowed transitive verbs are systematically classified with verbs taking less affected Ps regardless of the degree of affectedness of their P. Lelepa has serial verb constructions but has also developed other verbal constructions grouped in the class of complex predicates, which comprise auxiliary verbs, serial verbs, post-verbs and clause-final particles. These encode a broad range of semantic distinctions including aspectual, modal and directional values, manner, intensification, cause-effect and result.