The purpose of this study was to examine the moderated mediating effect of maladaptive cognitive emotion regulation strategies through academic stress on the relationship between socially-prescribed perfectionism and test anxiety. A total of 604 Korean high school students, including 367 males and 237 females, participated in this study by responding to the following questionnaires: Multidimensional Perfectionism Scale (HMPS), Academic Stress Scale, Korean version of Cognitive Emotion Regulation Questionnaire (K-CERQ), Test Anxiety Inventory-Korea (TAI-K). The collected data were analyzed using SPSS Macro. The main findings were as follows. First, using three-step mediated regression analysis, the significant partial mediating effect of academic stress on the relationship between socially-prescribed perfectionism and test anxiety was found. Second, using hierarchial multiple regression analysis, it was found that maladaptive cognitive emotion regulation strategies moderatedthe relationship between academic stress and test anxiety. Third, using SPSS Macro, the moderated mediating effect of maladaptive cognitive emotion regulation strategies (especially, rumination, self-blame, and catastrophizing) on the relationship between socially-prescribed perfectionism, academic stress, and test anxiety was found. Based on the result of this study, we discussed several implications for counseling and education, limitations of the study, and suggestions for future research.