Background ?More than half of children and adolescents have experienced headache within the last 3 months. Several risk factors for headache have been identified, including obesity and lack of sleep. The association between screen time and headache in children and adolescents is sparsely investigated. The aim of this study was to assess this association and evaluate if it varied according to headache diagnosis. Method ?This cross-sectional study was performed at the tertiary pediatric outpatient clinic for headache at Herlev University Hospital. A total of 139 participants who answered a questionnaire on lifestyle factors and their daily living were included. Diagnoses of migraine and tension-type headache (TTH) were made according to the International Classification of Headache Disorders-3. Children with both migraine and TTH were allocated to a mixed headache group. We differentiated between total, leisure, and school-related screen time. Results ?The mean age was 13.20 ± 3.38 years and 53.2% were girls. Note that 25.2% were diagnosed with migraine without aura, 23.0% migraine with aura, 28.1% TTH, 15.8% mixed headache, and 7.9% had an unclassified headache diagnosis at the time of inclusion. There was no statistically significant difference in screen time across the five headache groups. An association between screen time and headache frequency was found in children with migraine with aura. Conclusion ?In this study, we investigated the association between screen time and headache in children and adolescents. More screen time was associated with more frequent headaches in children with migraine with aura. Future prospective studies are needed to determine the causality of this association.