The coronavirus disease 19 (COVID-19) pandemic negatively affected children’s health in the United States (US), with more severe disruption for marginalized groups. However, potential impact on pediatric chronic pain has not been assessed at the population level. This study aimed to (1) estimate differences in the US national prevalence of pediatric chronic pain during the first year of the COVID-19 pandemic (2020), relative to one year earlier (2019); (2) determine whether differences in prevalence varied across sociodemographic groups; and (3) explore changes in child, caregiver, and family factors associated with chronic pain prevalence. Using data of children 6 to 17 years from the National Survey of Children’s Health 2019 and 2020 (n = 50,518), we compared weighted percentages of sample characteristics by year and conducted a series of directed-acyclic graph-informed survey-weighted Poisson regressions. The estimated national prevalence (95% CI) of pediatric chronic pain was 10.8% (9.9, 11.9%) in 2019, decreasing to 7.6% (6.9, 8.3%) in 2020. Contrary to hypotheses, the adjusted prevalence of chronic pain was 31% lower in 2020 than in 2019 (aPR = 0.69, 95% CI: 0.61, 0.79), adjusting for child age, sex, race or ethnicity, caregiver education, neighborhood park or playground, and census region. The 2019 to 2020 change in chronic pain prevalence was similar by age (P = 0.34), sex (P = 0.94), race or ethnicity (P = 0.41), caregiver education (P = 0.49), neighborhood park or playground (P = 0.22), and census region (P = 0.20). Exploratory analyses identified 3 potential contributors to the unexpected decrease in the national prevalence of pediatric chronic pain: lower prevalence of bullying, more frequent family meals, and higher family resilience.