Women's social experiences can have long-term implications for their offspring's health, but little is known about the potential independent contributions of multiple periods of stress exposures over time. This study examined associations of maternal exposure to adversity in childhood and pregnancy with children's anxiety and depression symptoms in a large, sociodemographically diverse sample. Participants were 1389 mother-child dyads (child age M = 8.83 years; SD = 0.66; 42% Black, 42% White; 6% Hispanic) in the ECHO-PATHWAYS Consortium's three U.S. pregnancy cohorts. Women reported their exposure to childhood traumatic events (CTE) and pregnancy stressful life events (PSLE). Children self-reported on their symptoms of anxiety and depression at age 8-9 years. Regression analyses estimated associations between maternal stressors and children's internalizing problems, adjusting for confounders, and examined child sex as a modifier. Exploratory interaction analyses examined whether geospatially-linked postnatal neighborhood quality buffered effects. In adjusted models, PSLE counts positively predicted levels of children's anxiety and depression symptoms ([ßAnxiety=0.08, 95%CI [0.02, 0.13]; ßDepression=0.09, 95%CI [0.03, 0.14]); no significant associations were observed with CTE. Each additional PSLE increased odds of clinically significant anxiety symptoms by 9% (95%CI [0.02, 0.17]). Neither sex nor neighborhood quality moderated relations. Maternal stressors during pregnancy appear to have associations with middle childhood anxiety and depression across diverse sociodemographic contexts, whereas maternal history of childhood adversity may not. Effects appear comparable for boys and girls. Policies and programs addressing prevention of childhood internalizing symptoms may benefit from considering prenatal origins and the potential two-generation impact of pregnancy stress prevention and intervention.