School segregation is 1 of the mechanisms through which structural racism undermines the health of Black children in the United States.1,2 In this issue of Pediatrics, Wang et al3 examined how exposure to school segregation was associated with health outcomes among Black children represented in the longitudinal Panel Study of Income Dynamics (PSID). Using a quasi-experimental design, the authors focused on the impact of resegregation within school districts released by the courts from previous desegregation orders. The authors fit instrumental variable (IV) models to isolate this impact of school resegregation from the health consequences of residential segregation and other confounding factors. Based on the IV analysis, the authors found that school resegregation attributable to the lifting of desegregation orders was associated with increases in behavioral problems and drinking alcohol among Black youth. Yet, overall levels of school segregation were not associated with these or other health outcomes in the analysis which used conventional multivariable adjustment. As such, the results of Wang et al3 underscore the need to better understand how and when school segregation most threatens the health of Black children.Resegregation of US schools is linked to a series of court decisions beginning in the 1970s, which released school districts from responsibility to undo the persistent segregation of Black and White children.4 Releases from desegregation orders accelerated in the 1990s, providing the basis for the IV analysis used by Wang et al.3 This history of school resegregation reveals the extent to which school resegregation is politically driven, and not only reflective of residential segregation.5 Indeed, more recent cohorts of Black children have experienced increasing exposure to school segregation, even as levels of Black-White residential segregation have trended downward.6,7 Several aspects of the school system have been implicated in the resurgence of school segregation, including enrollment in private and charter schools and growing disparities between adjoining school districts.8,9 However, some research suggests that the most consequential actions for school resegregation are those of individual school districts.9,10 For example, in a case study of 3 school districts in areas with high residential segregation, the 2 districts which actively considered diversity in student assignment policies achieved meaningfully lower levels of school segregation.10The importance of local context for school resegregation presents a challenge to analyzing health outcomes of resegregation in national data sets such as the PSID. Despite its nationally representative design, the PSID was not intended to generate estimates for small geographies, and in the current study, a sample of only 1248 Black children was available to represent ∼1000 school districts that had been under desegregation orders in 1991.3 This limitation, coupled with the statistical inefficiency of IV methods, suggests that the current study likely underestimated the impact of school resegregation on health. Furthermore, Black children’s exposure to school segregation is highest in the elementary grades,6 whereas many of the health outcomes available in the PSID are more applicable to older children and adolescents (eg, smoking and drinking). As such, measures of health status, health care access, and development tailored to evaluating younger children might have revealed more fully the adverse effects of school resegregation.Despite these limitations, the work of Wang et al3 is a timely reminder that the harms of school segregation persist and extend beyond the schoolhouse walls. During the ongoing coronavirus disease 2019 pandemic, the rise of virtual learning has contributed to further segregation of the educational experience, even among children nominally enrolled in the same schools and classes. Notwithstanding larger structural forces, such as residential segregation, and the role of individual families’ beliefs and choices, recent research suggests that action at the level of schools and districts can have critical implications for exacerbating or reversing trends in school resegregation.8,10 Building on the current study, future work leveraging local health data would help reveal how advocacy at this level can undo the harm school segregation has caused and is continuing to cause.