Aim Studies reporting factors associated with paediatric/adolescent acute behavioural disturbance (ABD) in the Emergency Department (ED) are lacking. The aim of this study is to describe paediatric/adolescent ED presentations involving ABD events. Methods A retrospective chart review of presentations involving ABD events, identified via hospital security log, to a tertiary referral paediatric ED during the 2017 calendar year. Data reported included: cause of presentation, use of sedation/physical restraint, ED/inpatient length of stay (LOS) and time requiring security staff presence. Results From 280 reported ABD episodes 26 were excluded leaving 254 events involving 150 patients across 233 presentations of whom 38 (25.3%) presented on multiple occasions. Median age was 14 years (interquartile range (IQR): 13–16), 132/233 (56.7%) were female, 167/233 (71.7%) primary mental health complaints, 30/233 (12.9%) deliberate self‐harm, 18/233 (7.7%) deliberate self‐poisoning, 11/233 (4.7%) acute intoxication and 7/233 (3.0%) other. Transport to hospital involved police and ambulance in 124/233 (53.2%), ambulance only 71/233 (30.5%), police only 16/233 (6.9%), relative or carer 20/233 (8.6%), with self‐presentation in 2/233 (0.9%). Sedation or physical restraint was used in 81/233 (34.8%), both 38/233 (16.3%), restraint only 26/233 (11.2%) and sedation only 17/234 (7.3%). Intra‐muscular droperidol accounted for 57/96 (59.4%) sedations, IM/IV benzodiazepines 15/96 (15.6%), IM/IV ketamine 5/96 (5.2%) and 19/96 (19.8%) other. Discharge from ED occurred in 171/233 (73.1%) with median ED LOS 5.1 h (IQR: 3.5–7.7) and median hospital LOS 92.4 h (IQR: 47.5–273.4) for those admitted. The Mental Health Act was utilised in 183/233 (78.5%) presentations. Median security staff time requirement per presentation was 2.4 h (IQR: 1.0–3.9). Conclusions Paediatric/adolescent ED presentations involving ABD are primarily due to mental health complaints. Less than half require the use of sedation/physical restraint. Time requiring security staff involvement is a significant resource consumption.