This study sought to examine the effect of maternal-child interactive play therapy on maternal-child interaction and child problem behavior. The study participants comprised three parents and children who submitted their consent; child problem behavior was defined as showing irritation, screaming, and interrupting conversations to attract attention among children aged 4–5 years who were attending H Daycare Center in District A in the U region. The results of this study are as follows: first, maternal-child interaction play therapy positively changed the play situation in circumstances in which parent-child interaction is free-flowing and the interaction was held in the home; second, maternal-child interaction play therapy had a positive effect on reducing problem behaviors at home and in daycare centers. Thus, it is confirmed that maternal-child interaction play therapy is effective in improving maternal-child interaction and reducing problem behavior in children.