Although Austronesian languages display a wide range of formal reduplicative patterns, multiple reduplication is reported only for Thao and Mokilese, and is practically unattested in Western Oceanic languages, including those of the Northwest Solomonic (NWS) subgroup. This paper investigates the functions and typologically rare patterns of multiple reduplication in Papapana, a previously undescribed and undocumented, highly endangered language (NWS, Western Oceanic) of Papua New Guinea. Both derivational and inflectional reduplication in Papapana involve leftward, monosyllabic or disyllabic copying. Inflectional reduplication always occurs in combination with another morpheme: (i) negative markers in prohibitives, (ii) the reciprocal marker vei in reciprocal constructions, or (iii) postverbal subject-indexing enclitics to express imperfective aspect. Although monosyllabic and disyllabic copying are typically Oceanic, some verbs in Papapana also display the cross-linguistically rare phenomenon of multiple reduplication to make a distinction between subtypes of imperfective aspect. Papapana also has unusual reduplication constructions because the preverbal comitative applicative marker me and the preverbal reciprocal marker vei can be reduplicated instead of the verb, and despite allowing multiple reduplication in imperfective aspect constructions, it is not permitted in constructions expressing both imperfective and reciprocal meanings. These features of Papapana reduplicative constructions call into question the status of the reduplicant as an affix or clitic, and the nature of multiple reduplication as a unitary or serial process, and these issues are debated in light of a typological comparison with related and unrelated languages.