BACKGROUND: Maternal depression is negatively associated with cognitive development across childhood and adolescence, with mixed evidence on whether this association differs in boys and girls. Herein, we performed a systematic review and meta-analysis of sex-specific estimates of the association between maternal depression and offspring cognitive outcomes. METHOD: Seven databases (PubMed, EMBASE, PsycINFO, ERIC, CINAHL, Scopus, ProQuest) were searched for studies examining the longitudinal association between maternal depression and offspring (up to 18 years) cognitive outcomes. Studies were screened and included based on predetermined criteria by two independent reviewers (Cohen's κ = 0.76). We used random-effects models to conduct a meta-analysis and used meta-regression for subgroup analyses. The PROSPERO record for the study is CRD42020161001. RESULTS: Twelve studies met inclusion criteria. Maternal depression was associated with poorer cognitive outcomes in boys [Hedges' g = -0.36 (95% CI -0.60 to -0.11)], but not in girls [-0.17 (-0.41 to 0.07)]. The association in boys varied as a function of the measure of depression used (b = -0.70, p = 0.005): when maternal depression was assessed via a diagnostic interview, boys [-0.84 (-1.23 to -0.44)] had poorer cognitive outcomes than when a rating scale was used [-0.16 (-0.36 to 0.04)]. CONCLUSIONS: This review and meta-analysis indicates that maternal depression is only significantly associated with cognitive outcomes in boys. Understanding the role of sex differences in the underlying mechanisms of this association can inform the development of targeted interventions to mitigate the negative effects of maternal depression on offspring cognitive outcomes.Read less <