10.60933/PRDR/PVQJ68 LO, Kin Ming Camilla PolyU Research Data Repository 2025 The data set contains screen time and health measurements of a representative sample of primary school children (N = 1428) in Hong Kong across two measurement time points over a period of one year from June 2021 (T1) to August 2022 (T5). Parents of the children completed the questionnaires. The data set also contains a sub-sample of 337 parents who were randomly selected from the larger sample. They completed additional questionnaires at 3-month intervals (T2, T3, and T4). LO, Kin Ming Camilla(The Hong Kong Polytechnic University)