By behaving altruistically, individuals voluntarily reduce their benefits in order to increase their partners'. This deviation from a self-interest-maximizing function may be cognitively demanding, though. This study investigates whether altruistic sharing in 4- to 6-year-old children, assessed by a dictator game (DG), is related to three measures of executive functioning, that is, inhibitory control, working memory, and cognitive flexibility. We found that children who turned out to be altruistic in the DG performed better on an inhibition task than non-altruists did. This finding lends support to the hypothesis that altruistic sharing might be somewhat constrained by the child's ability to inhibit a natural tendency to preserve his or her own resources. Much research is needed to understand the role of inhibitory control in the development of costly sharing and the consolidation of inequity aversion.