This study examined the relationships between parenting stress, parenting sense of competence, and parenting behavior in Korean and Japanese mothers of early school-aged children. A sample of 166 Korean mothers and 112 Japanese mothers completed questionnaires. First, in terms of results, Korean mothers reported higher scores in parenting stress, parenting sense of competence, and warmth and neglect than Japanese mothers did. In contrast, Japanese mothers scored higher on intrusiveness than Korean mothers. Second, for both groups, parenting stress was negatively related to warmth and reasoning, and positively related to intrusiveness, coercion, and neglect. Third, for both groups, parenting sense of competence was positively linked to warmth and reasoning, and negatively linked to intrusiveness, coercion, and neglect. Fourth, parenting stress was negatively associated with parenting sense of competence for both groups. Finally, parenting sense of competence mediated the associations between parenting stress and warmth for both groups. Only in the case of Korean mothers did parenting stress influence reasoning and intrusiveness through parenting sense of competence. These results imply that there may indeed be cross-cultural similarities and differences in three parenting-related variables between Korean and Japanese mothers.