AimTo characterise key features of young people presenting to the emergency department (ED) with a mental health complaint when comparing children (aged 7 to 12 years) and teenagers (13 years and greater).MethodsRetrospective review of all ED mental health presentations in children aged 7–17 years presenting over a 12‐month period in 2018 to a tertiary children's hospital in Victoria, Australia. Univariate analyses were carried out to examine the relationship between children and teenagers and a number of key presentation variables. Odds Ratios (ORs) and 95% Confidence Intervals (CIs) were calculated for ED management outcomes.ResultsThere were 1691 ED mental health presentations in 2018. Of these presentations, 407 (24%) were children aged 12 years or less. The remaining 76% (1284) were teenagers. The younger aged cohort were more likely to be male (OR 2.43, CI 1.92–3.08) and have a past history of autism spectrum disorder (OR 1.92, CI 1.45–1.84). They were more likely to have a presenting complaint of acute behavioural disturbance (OR 2.03, CI 1.59–2.60), be physically restrained (OR 2.01, CI 1.18–3.37) and have sedative medication provided (OR 2.87, CI 1.63–5.04). The older aged cohort were more likely to have a past history of depression (OR 0.19, CI 0.12–0.29) and a presenting complaint of intentional self‐poisoning (OR 0.33, CI 0.15–0.65).ConclusionsChildren aged 12 years or less represent one‐quarter of all young people presenting to the ED with a mental health concern. They experience high rates of acute behavioural disturbance and are more likely to require restrictive interventions during their presentation.