We investigated bias in self-perceptions of competence (relative to parent ratings) for family, school, and peer domains as predictors of adjustment problems among 139 young adolescents over a 1-year period using a prospective design. Regressions examined measures of bias at Time 1 (T1) as predictors of ratings of internalizing and externalizing problems at Time 2 (T2), controlling for T1 adjustment ratings. For the family domain, curvilinear trends were found. Follow-up analyses revealed that for this domain both negative bias (self-perceptions less favorable than parent ratings) and positive bias (self-perceptions more favorable than parent ratings) predicted greater internalizing and externalizing problems as rated by youth, parents, and teachers. For the peer domain, higher scores on the measure of bias predicted greater internalizing and externalizing problems as rated by teachers. These findings are consistent with the view that accuracy in self-perceptions of competence can have important implications across multiple domains of development.