Background Procedural sedation is routinely provided for children in the emergency care setting. However, there are still significant gaps in knowledge regarding the optimal provision of sedation for children who are undergoing painful and/or distressing procedures. We aimed to develop a prioritised research agenda that identifies key questions for paediatric procedural sedation in the emergency care setting that will guide future research and optimise care for children. Methods We used a modified Delphi approach to achieve consensus among a multidisciplinary and geographically diverse expert advisory group. An initial list of 42 research questions was identified, with successive rounds of questionnaires conducted until there was a convergence of opinion or a point of diminishing returns was reached. The list was iteratively refined each round by advisory group members who ranked research questions and were given the opportunity to provide suggestions for potential additional questions and provide feedback regarding questions considered. Results 54 advisory group members participated in the modified Delphi approach. Over the course of two rounds, we identified 10 research questions as the highest priority for future investigation. These questions included topics addressing short- and long-term outcomes related to inadequate assessment and provision of sedation, patient-centered and family-centered outcomes, validity and reliability of clinically important outcome measures, most effective sedative regimens for children undergoing painful procedures, most effective sedative regimens for children undergoing non-painful procedures, most effective sedatives for minimal sedation/anxiolysis, effectiveness of novel sedation approaches, eliminating health disparities, clinician education and competency and the use of simulation to improve sedation outcomes. Conclusions The 10 research questions identified as highest priority can inform future work by researchers, funders, policymakers and other key decision makers who aim to meaningfully advance the provision of procedural sedation for children cared for in the emergency care setting.