The purpose of this study was to examine whether maternal personality (i.e., Agreeableness and Conscientiousness) predicted maternal positive parenting (i.e., warmth/sensitivity and structure), and whether maternal parenting predicted children's regulation and sympathy and/or prosocial behavior. Additionally, the mediated effect of maternal warmth/sensitivity on the relation between maternal Agreeableness and children's regulation and the mediated effect of maternal structure on the relation between maternal Agreeableness and children's observed sympathy/prosocial behavior were investigated. Maternal personality was measured when children (N = 256 at Time 1) were 18 months old; maternal parenting was assessed when children were 18, 30, and 42 months old; children's regulation and sympathy/prosocial behavior (observed and reported) were assessed when children were 30, 42, and 54 months old. Mothers reported on their personality; maternal warmth/sensitivity was observed; maternal structure was observed and mothers also reported on their use of reasoning; mothers and caregivers rated children's regulation (i.e., effortful control [EC]) and regulation was also observed; mothers and fathers rated children's prosocial behavior; sympathy and prosocial behavior were also observed. In a path analysis, Conscientiousness did not significantly predict maternal warmth/sensitivity or structure at 30 months, whereas Agreeableness marginally predicted maternal warmth/sensitivity at 30 months and significantly predicted maternal structure at 30 months. Maternal warmth/sensitivity at 18 months significantly predicted 30-month EC, and 30-month maternal warmth/sensitivity significantly predicted 42-month EC. Maternal structure at 30 months significantly predicted 42-month observed sympathy/prosocial behavior. Maternal warmth/sensitivity at 42 months significantly predicted 54-month observed sympathy/prosocial behavior and marginally predicted 54-month reported prosocial behavior. Maternal structure and EC did not significantly predict reported prosocial behavior across any time point. EC did not significantly predict observed sympathy/prosocial behavior across any time point and maternal warmth/sensitivity at 18 and 30 months did not predict observed or reported sympathy/prosocial behavior at 30 or 42 months, respectively. Maternal Agreeableness directly predicted 30-month reported prosocial behavior and additional paths suggested possible bidirectional relations between maternal warmth/sensitivity and structure. Mediation analyses were pursued for two indirect relations; however, neither mediated effect was significant. Additional results are presented, and findings (as well as lack thereof) are discussed in terms of extant literature.