Objectives: This paper examines how serious the appearance concerns of adolescents is in South Korean society by delving into the formation and changes of adolescents' appearance concerns. Methods: We conducted a secondary analysis of the data of multi-year tracing surveys which the National Youth Policy Institute opened to the public. The repeated Measures ANOVA, the paired t-test, and a chi-squared test were applied against the data. Results: It was found that about one out of ten adolescents experienced concerns that began as early as the upper grades of elementary school, reached its peak in middle school, and decreased afterwards. On the other hand, some of them faced enduring appearance concerns and seemed to suffer from it. One interesting finding is that adolescents once relieved from the concerns were free from it permanently. We also found that there were considerable differences between male and female adolescents in terms of the level of concerns they experienced, their peak periods, and other characteristics. Conclusions: Appearance concerns changes dynamically according to development of adolescence. Appearance concerns was less prevalent among adolescents than predicted, and it seemed considerably fluid. Our study not only confirms but also challenges some important findings of previous studies.