This paper presents an account of the uses and functions of irrealis morphology on quantificational expressions in noun phrases in Unua, an Oceanic language of Vanuatu. I will show that, when present on such quantificational expressions, the irrealis morphology encodes two distinct semantic functions for the arguments so quantified. In the context of negation and/or of irrealis modality, the irrealis-marked argument identifies a low-scope existential. In contexts in which the irrealis-marked argument is the argument of an individual-level predicate, it identifies a high-scope universal.