Clearance of malaria parasites in the blood may involve complement proteins that can lead to merozoite lysis and inhibition of RBC invasion and replication. Opsonization of malaria blood-stages by antibodies and complement, which interact with complement receptors (CR) and Fcγ-receptors, can promote phagocytic clearance by monocytes and neutrophils. However, complement dysfunction and excessive activation of immune cells can also potentially contribute to pathogenesis of severe disease. Currently, there are limited data on complement and Fc-gamma receptor (FcγR) mediated responses in severe malaria. In this study we investigated, for the first time, antibodies that fix and activate complement or interact with different Fcγ-receptors to promote phagocytosis in a case-control study of severe malaria in 383 young children in Papua New Guinea (PNG). Our results show that IgG and complement (C1q) fixing antibodies were significantly lower in children with severe malaria compared to children with mild uncomplicated malaria (p=0.04 and p=0.02 respectively). IgG strongly correlated with functional antibodies in both severe and uncomplicated malaria. Further, children with broad antibody multi-functional activity had a significantly reduced odds of severe disease. Our results show differences in response types between severe and uncomplicated disease among children that provide new insights into mechanisms that could be exploited in vaccine development to provide protection against severe disease.