The COVID-19 lockdown has had pervasive effects on children, including school closures, a shift to remote learning, and suspension of youth sports and recreational activities. Children gain weight at an accelerated rate when not in school (1), which has been attributed to greater engagement in obesogenic behaviors when children's days are unstructured (2). There is emerging evidence that children's physical activity, sedentary time, eating patterns, and sleep routines deteriorated during the COVID-19 lockdown (3-7) and that normalweight children gained weight at an alarming pace (8). The degree to which the pandemic interfered with weightmanagement efforts among children with overweight or obesity has not been reported, to our knowledge, to date, particularly in low-income, racially diverse populations. Standard-of-care pediatric weight-management interventions generally produce modest, but sustained and meaningful, reductions in weight (9). However, their efficacy may have been diminished during the COVID-19 lockdown. Understanding the impact of the pandemic on weightmanagement interventions is important for ongoing treatment planning and for interpreting the results of pediatric obesity treatment trials conducted during this period. This study leveraged data from 230 low-income families participating in a clinical trial to examine the change in efficacy of structured, family-based pediatric obesity treatment delivered before versus during the COVID-19 lockdown.