Women are at an increased risk for the development of perinatal mood and anxietydisorders which affect mother-child interactions and children’s socioemotional and regulatory development. This work explores how the timing of maternal mental health and stress impacts maternal and observer perceptions of children’s problem, competence, and regulatory behaviors and assesses the potential moderating role of maternal sensitivity. Pregnant mothers (N=149) completed questionnaires and laboratory-based assessments during the first two postpartum years. A subsample of mothers (N=105) completed a survey to explore the long-term effects of maternal stress on their child’s (Mage = 6.05 years) response to the COVID-19 pandemic. Results highlight the predictive power of perinatal (but not preconception) maternal mental health and stress variables when considering maternal-reported (but not observer-reported) child problem and competence behaviors. No significant findings emerged when predicting child regulatory behaviors or pandemic responses and maternal sensitivity did not emerge as a significant moderator. Our findings support the link between perinatal adversity and later child socioemotional behaviors when assessed via maternal report. The predictive role of demographic variables, procedural constraints, clinical implications, and limitations are addressed.