There has been extensive debate among scholars and practitioners concerning whether self-beliefs influence academic achievement. To address this question, findings of longitudinal studies investigating the relation between self-beliefs and achievement were synthesized using meta-analysis. Estimated effects are consistent with a small, favorable influence of positive self-beliefs on academic achievement, with an average standardized path or regression coefficient of .08 for self-beliefs as a predictor of later achievement, controlling for initial levels of achievement. Stronger effects of self-beliefs are evident when assessing self-beliefs specific to the academic domain and when measures of self-beliefs and achievement are matched by domain (e.g., same subject area). Under these conditions, the relation of self-beliefs to later achievement meets or exceeds Cohen's (1988) definition of a small effect size.