Exposure to childhood trauma confers intergenerational risk on child development. However, the mechanism linking a mother's childhood trauma with her child's cognitive development remains poorly understood. This study recruited 71 mother-child dyads affected by substance use disorder from local, community-based, outpatient substance use treatment programs. Maternal exposure to childhood trauma, caregiving behavior, and child cognitive development were assessed in each mother-child dyad. These were measured through a comprehensive biopsychosocial interview, an observed dyadic interaction coded using the Coding Interactive Behavior system, and the Bayley Scales of Infant and Toddler Development, Screening Test, respectively. We hypothesized that compromised caregiving behavior would mediate a negative relationship between maternal childhood trauma and child cognitive development. Analyses did not support this hypothesis. Specifically, maternal childhood trauma was not significantly associated with child cognitive development nor the four dimensions of maternal caregiving behavior. However, caregiving behavior (specifically maternal sensitivity and limit setting) was associated with child cognitive development, when controlling for maternal childhood trauma and child age. The lack of associations observed suggests that protective factors may buffer the intergenerational impact of childhood trauma. Furthermore, the relationship between quality of caregiving and child cognitive development highlights the importance of interventions which foster sensitive caregiving behaviors that may bolster child cognitive development in the context of maternal substance use disorder and maternal childhood trauma. (PsycInfo Database Record (c) 2024 APA, all rights reserved).