This research aimed to examine whether and why children hold favorable self-conceptions (total N = 882 Dutch children, ages 8–12). Surveys (Studies 1–2) showed that children report strongly favorable self-conceptions. For example, when describing themselves on an open-ended measure, children mainly provided positive self-conceptions—about four times more than neutral self-conceptions, and about 11 times more than negative self-conceptions. Experiments (Studies 3–4) demonstrated that children report favorable self-conceptions, in part, to live up to social norms idealizing such self-conceptions, and to avoid seeing or presenting themselves negatively. These findings advance understanding of the developing self-concept and its valence: In middle and late childhood, children's self-conceptions are robustly favorable and influenced by both external (social norms) and internal (self-motives) forces.