AimThe main aim of this study was to examine the aetiology and the yield of brain imaging of children with site locked headaches (SLH). MethodsThis study was carried out at Queen's University Hospital, Essex, UK, from August 2011 to August 2015 and focused on patients who were at least five years of age, had experienced at least five SLH attacks and had a normal neurological examination. Bilateral or alternating unilateral headaches were excluded. Data were collected prospectively, and the headache diagnosis was based on the International Classification of Headache Disorders. ResultsWe identified 292 eligible patients (60% female) aged 5.1-17 years: 177 with unilateral SLH, 104 with occipital SLH and 11 with vertex SLH. Anterior headaches were the most frequent (n = 133), and the diagnoses included migraine (n = 192), tension type headaches (n = 30) and medication-overuse headaches (n = 22). The headache was unspecified in 43 cases. Magnetic resonance imaging was normal in 96% of the 283/292 scanned or showed a nonspecific, nonsignificant abnormality in 4%. ConclusionSite locked headaches were most likely to be caused by primary headaches, particularly migraine. An SLH without abnormal neurological findings is unlikely to have an underlying sinister aetiology, and routine brain imaging is not required in such cases.