Issue Addressed: The recommended first aid for burns, consisting of 20 minutes of cool running water (CRW) delivered within three hours of the injury, offers a simple yet effective means of improving health outcomes. The aim of this study was to determine patient and injury characteristics associated with inadequate CRW therapy among children with thermal burns, with the goal of identifying populations at greatest risk of undertreatment. Methods: A cross-sectional study was performed on children treated at a large tertiary paediatric burns centre. First aid was evaluated as either “adequate” or “inadequate”, and then descriptive analyses were conducted to examine differences between the groups in age, ethnicity, location and socioeconomic status, among others. Results: From 2013 to 2016, the families of 2522 patients were interviewed. Overall, 31.3% of children received adequate CRW at the scene of the injury. Provision of adequate CRW did not significantly differ with sex, ethnicity or nationality. Factors that were associated with inadequate first aid included very young age and early adolescence (P < 0.001), rural or remote location (P = 0.045), low socioeconomic status (P = 0.030), radiant heat and flame burns (P < 0.001), as well as burns occurring at recreational sites, on farm/trade/industrial properties and in the street (P = 0.001). Conclusions: Although most burns occurred in close proximity to sources of CRW, first aid was poor across all demographics. The highest levels of undertreatment were found in children aged 0-2, adolescents aged 15-16, those living rurally or remotely, and the socioeconomically disadvantaged. So what?: The study highlights the need for improved public education of first aid for burn injuries.