Background: The frequently reported decline in the "overall" frequency and intensity of fears during late childhood and adolescence may mask different developmental patterns for two broad subclasses of fears: fears concerning physical danger and fears concerning social evaluation. It was investigated if physical fears decrease between late childhood and mid-adolescence, while social-evaluative fears increase during this period. It was also studied if changes in both sets of fears are more strongly related to socio-cognitive maturity than to age, which itself is only a proxy measure of maturity. Methods: A non-clinical sample of 882 children and adolescents (ages 8-18) was recruited for study. Fears were assessed using the Ollendick Fear Survey Schedule for Children-Revised (FSSC-R). A Principal Components Analysis (PCA) was conducted to study the factor structure of the Failure and Criticism subscale of the FSSC-R. Level of development was assessed using the Sentence Completion Test for Youth (SCT-Y), a measure of socio-cognitive maturity that is based on Loevinger's model, and measure, of ego development. Results: The PCA of the Failure and Criticism subscale revealed three factors: Social Evaluation, Achievement Evaluation, and Punishment. As predicted, the significant decrease of overall fearfulness obscured two contradictory developmental patterns: (a) fears of physical danger and punishment decreased with age, whereas (b) fears of social and achievement evaluation increased with age. Hierarchical regression analyses showed that the age effect for social-evaluative fears was explained entirely on the basis of developmental differences in socio-cognitive maturity (controlling for verbal ability). In contrast, age was a better predictor of the decrease of physical and punishment fears (although socio-cognitive maturity still added to the predictive value of age). Conclusion: The expression of social evaluation fears during adolescence appears not atypical and might be a corollary of socio-cognitive maturation. At the same time, the natural presence of those fears during adolescence appears to constitute a vulnerability for developing a social anxiety disorder.