Loneliness is a significant problem that predicts immediate and long-term negative outcomes for young children. This study examines the mediating effect of children's play disconnection on the relationship between their shyness and loneliness, as well as the moderating effect of children's perceived child-teacher intimate relationship on the relationships between child shyness, play disconnection, and loneliness. Participants include 171 4 to 6 year old South Korean children and their teachers and mothers. Children's teachers were asked to respond to the questions measuring child shyness and play disconnection, and the mothers assisted their children to answer the questions measuring child loneliness and child-teacher intimate relationship. The results of the study are as follows. First, child shyness affected loneliness via play disconnection. Second, child-teacher intimate relationship moderated the relationships between child shyness and loneliness and between child shyness and play disconnection. However, the association between play disconnection and loneliness was not moderated by child-teacher intimate relationship. The findings of the study suggest that teachers not only provide shy children with emotional support but also build affectionate and intimate relationships with them to support their peer play and to reduce their feelings of loneliness.