In a 4-wave, 2-year longitudinal design, the authors obtained measures of negative affect (NA) and self-perceived competence from 220 boys and 216 girls who were 7th graders at the beginning of this study. NA was operationalized as the common dimension underlying self-reports of depressive symptoms, anxiety symptoms, and negative emotions. Self-perceived competence consisted of 2 higher order constructs: a well-behaved/good-student factor and an attractive/athletic/popular factor. Structural equation modeling revealed very high stability estimates for all constructs. Nevertheless, self-perceived competence in the attractive/athletic/popular domain predicted changes in NA. Conversely, NA predicted changes in self-perceived competence in the well-behaved/good-student domain. The primacy of NA versus self-cognitions depends, in part, on the type of self-cognitions being examined.