Background: The COVID-19 pandemic disrupted family life, with disproportionate impacts on families who are racially and economically marginalized. Decades of developmental research emphasize how caregivers' or children's emotional responses to stressors shape children's post-exposure adaptation. Less work has examined the intersection of parents' and children's lived experiences of the pandemic, and their co-contribution to children's adaptation. Objective: The study's goal was to examine both COVID-related and lifetime stressors and their associations with maternal perception of children's emotional regulation and distress in the context of the COVID-19 pandemic. Methods: In a sample of 72 mothers and their children (M = 7.94 years) who are American, low-income, and predominantly Black, we examined whether parent-reported maternal and child factors co-contributed to children's emotion regulation and COVID-related distress. Between November 2020-March 2021, mothers reported on their emotion regulation difficulties, their child's emotion regulation, their child's lifetime exposure to stressors, their child's exposure to COVID-specific stressors, and their own and their child's perception of COVID-related disruptions as distressing. Results: Our results parse differential predictors: children's lifetime stressor exposure and maternal emotion regulation difficulties predicted children's emotion regulation; children's exposure to COVID-related stressors, maternal subjective COVID-related stress, and maternal emotion regulation difficulties predicted children's subjective COVID-related stress. Conclusions: Although limited by reliance on parent report, findings highlight the importance of considering children's experiences of distress and emotion regulation during the COVID-19 pandemic in broader contexts, including the context of parent's own regulatory capacities and perceptions of stress, as well as children's lifetime experiences of stressors.