Reputational concerns are known to promote cooperation. Individuals regularly act more prosocially when their behavior is observable by others. Here, we investigate 4- and 5-year-old (N = 144) children's reputational strategies in a competitive group setting. The aim of the current study was to explore whether children's sharing behavior is affected by the future possibility of being singled out publicly as the most generous or, alternatively, the least generous member of the group. Children were told that they could share stickers with other children and that the picture of either the (1) most generous or (2) least generous donor would be displayed publicly. In both conditions, children shared significantly more than in a control condition. Moreover, 5-year-old, but not 4-year-old children's sharing was affected more by the possibility of being presented as the most generous than being presented as the least generous member of the group. This study is the first to show that children as young as 4 invest in their future reputation and that by age 5 children flexibly apply different reputational strategies depending on context.