We examined effects of maternal and child lifetime traumatic stress exposures, infant temperament, and caregiving quality on parent ratings of preschoolers' executive functioning (EF). Maternal lifetime trauma was associated with preschoolers' EF problems; this association was mediated by greater child trauma exposure. Infant temperament was associated with EF abilities, particularly among females. Among males, infant extraversion/surgency mediated the association of maternal lifetime trauma with poorer child EF. Caregiving quality was negatively associated with maternal and child trauma exposures but did not predict child EF. Findings have implications for interventions to identify children at risk for poor EF and optimize outcomes.