AbstractTo be able to develop effective policy and targeted support for children and young people, it is vital to develop and validate measures that enable us to understand what aspects of pandemics are associated with anxiety and stress across a wide age range. We examined the psychometric properties of the Pandemic Anxiety Scale– Parent-report (PAS-P), which measures levels of child and adolescent pandemic-related anxieties. Factor structure, reliability, and convergent and discriminant validity of the PAS-P was assessed in a convenience sample of parents/carers (N = 8410) over at three time points in 2020 when COVID-19 case rates and restrictions varied. Factor structure was identified via two exploratory factor analyses (EFAs; n = 5601 and n = 1005) and then tested using confirmatory factor analysis (CFA; n = 800), measurement invariance tests, and a longitudinal CFA (n = 1651). Two factors structure for disease and consequence anxiety were observed across both EFAs and were found to have good fit in the CFAs. The PAS-P demonstrated good internal consistency and discriminant validity, as well as partial scalar invariance in latent construct measurement across child age, gender, and time. The PAS-P is a robust parent-report measure of two distinct forms of pandemic-related anxiety, suitable for reporting on children and adolescents aged 4-16 years. Although the scale has been validated in the context of the COVID-19 pandemic, it is not limited to this specific pandemic and, with minor wording modifications, may be a reliable tool in other health epidemic contexts.