The purpose of this study is to reveal the factors influential on adolescents' social competence within the frame of a model. Based on this purpose, the study was carried out in two phases. Initially, data were collected from 283 high school students for the validity and reliability studies of Positive-Negative Perfectionism Scale adolescent form. Confirmatory factor analysis and Cronbach's alpha internal consistency coefficient calculated based on the data indicated that the scale can be used with adolescents. The second phase of the study involved collection of data from 640 high school students to test the proposed model about social competence via path analysis. The path analysis results showed that positive and negative perfectionism, fear of negative evaluation, and academic competence have direct influences on social competence. In addition, fear of negative evaluation is a mediator in the relationship between negative perfectionism and social competence whereas academic competence is a mediator in the relationship between positive perfectionism and social competence. The results are discussed in light of literature. Some recommendations are made for mental health experts.