The present study examined the moderating effect of children's emotion regulation on the relations between shyness and internalizing behavior in Turkish preschool children. Participants were N = 222 children ( M = 58.20 months, SD = 11.24, 116 girls, 106 boys) attending five public kindergartens in Turkey. Mothers provided ratings of children's shyness and emotion regulation; teachers assessed children's internalizing behavior. Results indicated that shyness was positively associated with internalizing behavior and negatively associated with emotion regulation among Turkish preschool children. Moreover, children's emotion regulation significantly moderated the relationship between shyness and internalizing behavior. Specifically, among children with lower levels of emotion regulation, shyness was significantly and positively associated with internalizing behaviors while among children with higher levels of emotion regulation, shyness was not associated with internalizing behaviors. The current findings inform that the importance of improving children's emotional regulation to buffer the internalizing behaviors among Turkish shyness young children. The findings also highlight the importance of considering the meaning and implication of shyness for preschool children.