Perinatal exposure to SARS-CoV-2 may affect neurodevelopment before 12 months of age, but longer-term outcomes remain unknown. We examined whether antenatal or neonatal SARS-CoV-2 exposure compared with non-exposure is associated with neurodevelopment, respiratory symptoms, and health care usage in early childhood. This prospective national population-based cohort study was conducted in England and Wales, United Kingdom. We enrolled term-born children (≥37 weeks' gestation) with and without antenatal or neonatal exposure to SARS-CoV-2 infection by approaching parents of eligible children who were cared for in 87 NHS hospitals. Potential participants were identified through the national active surveillance studies of pregnant women and newborn infants hospitalised with confirmed SARS-CoV-2 infection conducted through the UK Obstetric Surveillance System and the British Paediatric Surveillance Unit. We defined antenatal and neonatal SARS-CoV-2 exposure as infants born to mothers hospitalised with confirmed SARS-CoV-2 infection between 14 + 0 and 36 + 6 weeks gestation and infants admitted to hospital with confirmed SARS-CoV-2 infection within the first 28 days after birth. Children born preterm or with major congenital anomaly or who were not residing in the UK were excluded. We assessed children's development (Ages and Stages Questionnaire 3rd Edition (ASQ-3); Ages and Stages Questionnaire Social-Emotional 2nd Edition (ASQ:SE-2)), respiratory symptoms (Liverpool Respiratory Symptom Questionnaire (LRSQ)) and health care usage (parent-completed questionnaire) at 21-32 months of age. Primary outcome: total ASQ-3 score, converted to z-scores. Secondary outcomes: ASQ:SE-2 z-scores; risk of delay in ASQ-3 domains; total LRSQ scores, converted to z-scores. Analyses were adjusted for children's age, sex, maternal ethnicity, parental education, and index of multiple deprivation. Between October 20, 2021 and January 27, 2023, we approached 668 and 1877 families out of 712 and 1917 potentially eligible participants in the exposed and comparison cohort. Of the 125 and 306 participants who were enrolled to the exposed and comparison cohort 121 and 301 participants completed the questionnaires and 96 and 243 participants were included in the analysis. In the age adjusted analysis, the mean total ASQ-3 z-score was lower in the exposed than the comparison cohort (-0.3, 95% CI: -0.6 to -0.05), however, when adjusted for sex, parental education, ethnicity and IMD quintile, there was no significant difference (difference in mean z-score = -0.2 95% CI: -0.5 to 0.03). SARS-CoV-2 exposure was associated with increased risk of delayed personal-social skills (odds ratio = 3.81; 95% CI: 1.07-13.66), higher ASQ:SE-2 total z-scores (difference in mean z-score = 0.4; 95% CI: 0.2-0.6) and increased risk of delayed social-emotional development (OR = 3.58, 95% CI: 1.30-9.83), after adjusting for sex, age at assessment, parental education, ethnicity and IMD quintile. The exposed cohort had a higher mean total LRSQ z-score than the comparison cohort (0.3 95% CI: 0-0.6) and higher inpatient (38% vs. 21%, p = 0.0001), outpatient (38% vs. 30%, p = 0.0090), and General Practitioner appointments (60% vs. 50%, p = 0.021) than the comparison cohort, after adjusting for sex, age at assessment, parental education, ethnicity and IMD quintile. No differences in other secondary outcomes between the exposed and comparison cohorts were found. Although the exposed cohort did not differ from the comparison cohort on the primary outcome, total ASQ-3 score, the exposed cohort were at greater risk of delayed social-emotional development, had a greater prevalence of respiratory symptoms and increased health care usage relative to the comparison cohort. The study is limited by the smaller sample size due to the low response rate and lack of clinical developmental assessments. Given the association of poor social-emotional development with antenatal or neonatal SARS-CoV-2 exposure, developmental screening, and follow-up of children with confirmed antenatal or neonatal SARS-CoV-2 infection may be warranted to identify those in need of early intervention. Action Medical Research for Children.