Scant research has examined links between particular emotion socialization processes and child emotion functioning cross-nationally. In this study, we assessed a sample of 55 families from the United States (U.S.; 28 boys and 27 girls) and 49 families from China (27 boys and 22 girls) on family emotional expressiveness and children’s emotional experiences and regulation. Results indicated that children and families from the U.S. reported greater emotional expressiveness than their Chinese counterparts. Children from the U.S. also reported greater undercontrolled emotion than Chinese youth. Family expression of positive emotion was related to effortful emotion regulation in U.S. youth only, whereas family expression of negative emotion was associated with undercontrolled emotion for both U.S. and Chinese children. Our findings advance context-specific models of emotional development by illustrating similarities and differences in emotional functioning among U.S. and Chinese families. From a clinical perspective, the findings suggest that practitioners should consider the cultural variations of emotion communication within families when conducting both assessment and therapy.