The purpose of this study is to devise guidelines for designing, developing, and using a smart toy for preschool children. Smart toys are technologically developed toys constructed with a meaningful purpose. This study uses the design and development research method. In the analysis phase, the smart toy developed in the pilot study was analyzed. In the design phase, focus group meetings were held with early childhood teachers to determine the objectives, story, and storyboard of the smart toy. In the development phase, two prototypes were developed, and formative evaluations were conducted with preschool children, early childhood teachers, and scholars. In the evaluation phase, the smart toy was evaluated by preschool children. Many design guidelines (categorized as content, visual design, or interaction) emerged during the study.