<ns3:p><ns3:bold>Background:</ns3:bold> Child wasting is highly prevalent, with around 49.5 million children under five years affected globally. More evidence is needed to inform the scale up of effective treatment of wasted children worldwide. The aim of this study was to identify and prioritise the main outstanding research questions relating to the treatment of wasting to inform future research agendas.</ns3:p><ns3:p> <ns3:bold>Methods:</ns3:bold> A research prioritisation exercise was undertaken using the Child Health and Nutrition Research Initiative method. Research gaps were identified from multiple sources, grouped in themes and condensed into a list of 53 research areas by a group of experts. An online survey was developed and circulated globally to individuals working in the global nutrition sector. Participants evaluated each research area according to four agreed criteria. Research areas were then ranked according to an overall research priority score.</ns3:p><ns3:p> <ns3:bold>Results:</ns3:bold> A total of 394 individuals from 63 countries participated in the survey. Research areas prioritised by the group focused on the effective detection and diagnosis of ‘high risk’ wasted children in the community; provision of a continuum of care; and early life course interventions. The group also prioritised evidence to inform guidance on the impatient management of wasted children with diarrhoea; prevention of post-treatment relapse and mortality; and the optimisation of ready-to-use therapeutic foods in treatment programmes.</ns3:p><ns3:p> <ns3:bold>Conclusions:</ns3:bold> Critical gaps in our understanding of the treatment of wasting must be filled to inform guidance, policy and programming to ensure that all wasted children receive the treatment services that they need. A coordinated research agenda across treatment and prevention is urgently needed to maximise the impact of funding investments towards the meeting of global targets to reduce child wasting.</ns3:p>