Intravenous immunoglobulin (IVIg) has been evaluated as an adjunctive therapy for neonatal sepsis with modest clinical success despite strong biological plausibility. Multiple factors contribute to this outcome, but perhaps none greater than the limited immune system function in newborns, especially in the very premature neonates. For very premature neonates (<30 weeks gestational age), understanding the effects of IVIg on specific immature immune system functions is particularly relevant given their preponderance to develop sepsis and therefore potentially benefit from IVIg-mediated immunoenhancement. Here, we review the available evidence for enhanced immune function after IVIg administration in very premature neonates and highlight areas for future research.