Two studies tested the novel hypothesis that children use social comparison (SC) for self-appraisal at an earlier age than they do temporal comparison (TC). The effect of other's and of own prior outcome on performance and ability appraisal and on self-evaluative strategies was examined using simple tasks and outcome information. Results from 840 children at ages 4–8 confirmed that self-evaluative SC was similar over age. Even 4-to 5-year-olds rated themselves higher after doing better versus worse than another and explained their ratings in terms of explicit SC. Social failure undermined continuing motivation at all ages. In contrast, young children in TC conditions attended only to their last outcome, and comparisons between current and prior outcomes increased with age. Self-evaluative biases were marked at age 5–6 and for boys in SC conditions. Results clarify the role of cognitive and motivational factors in the development of SC and TC.