Guided by the broaden-and-build model, the role that both parent and child positivity play in supporting children's self-regulation was examined. Specifically, parental positive emotional expression and emotion coaching were predicted to moderate the association of children's positive emotions to their self-regulation. Parents rated preschool-aged children's (n = 156) high-intensity and low-intensity pleasure. Parents’ positive emotional expression and emotion coaching were coded in an emotion talk task where parents discussed an upsetting event with children. Children's regulation was measured through observed distraction in a frustration task and parental rating of effortful control. Children's high-intensity pleasure was negatively associated with effortful control, whereas low-intensity pleasure was positively related to effortful control. Parents’ positive emotional expression when discussing an upsetting event was positively associated with children's distraction and effortful control and moderated the relation of child low-intensity pleasure to distraction. Parents’ positive emotion coaching was negatively related to children's effortful control and moderated the relation of children's low-intensity pleasure to distraction. Findings support the idea that parents’ socialization of positive emotion is related to children's own low-intensity positive emotion and their self-regulation during early childhood, which is a foundational period for the development of children's self-regulation.