Traumatic brain injury (TBI) is a leading cause of morbidity and mortality in children. Preventing secondary injury by controlling physiological parameters (e.g. intracranial pressure [ICP], cerebral perfusion pressure [CPP] and brain tissue oxygen [PbtO2]) has a potential to improve outcome. Low PbtO2 is independently associated with poor clinical outcomes in both adults and children. However, no studies have investigated associations between low PbtO2 and neuropsychological and behavioural outcomes following severe pediatric TBI (pTBI).