This is a case study on family therapy for a child showing inhibited behaviors, caused by dysfunctional family relationships. The causes of the inhibited behaviors included dysfunctional parenting skills of the child's mother, the mother's negative experiences with her family origin, confused nuclear family systems. The mother's dysfunctional parenting style and the child's behavioral inhibition formed a vicious cycle, feeding to each other. The mother's negative experiences with her family origin influenced on her dysfunctional parenting skills. The confused nuclear family system negatively impacted the child's inhibited behaviors and the mother's malfunctioning parenting methods. Thus, the family intervention focused on improving the child's self expression, forming the mother's parenting efficacy, and restructuring the family system. The child began to have better self expression, improve encopresis, decrease computer usage, and show better interpersonal skills. The mother also showed better communication and empathy skills and began to use permissive attitude and have stable emotions. Their family system changed to restore the mother-the child parental relationship, improve spousal relationship, form affectionate sibling relationship, and create stable emotional conditions within the system. Those results indicate that behavioral inhibition among children is closely related to parenting skills and family relationships and that intervening at family system level is effective to help them.