This qualitative study describes happiness of preschool children in four Islamic kindergartens in the urban area of Jakarta, Indonesia. The participant involved 353 children, including 165 boys and 188 girls, within four to six years. Data were collected through face-to-face interviews and face-scale, with the content. The result showed that children have high levels of happiness, with the majority considering play as a source of positive affect, followed by school performance, material issues, friendship, and family. In contrast, most reported sources of negative affect in children’s daily lives referred to the following categories: material issues, none, family, illness or injury, and friendship. Further studies are needed to analyze the implication of children s happiness on parents, social workers, and teachers by focusing on play activity.