The present study was conducted with the aim of assessing the relationship between social anxiety and academic performance of students. The research type is applied in terms of its purpose and descriptive-correlational in terms of its data collection method. The subject of this study was Islamic Azad University and its statistical population consisted of undergraduate students in the field of psychology at Islamic Azad University, Tonekabon Branch, of whom 142 people were selected as a statistical sample by simple random sampling. To collect research data, standard questionnaires of social anxiety by Jarabak (1996) and academic performance by Pham and Taylor (1999) were used. To determine the validity of the research tool, face and content validity were used, and to determine the reliability of the research tool, Cronbach's alpha coefficient was used. In order to analyze the collected data in the descriptive section, central indices (mean), dispersion indices (variance and standard deviation) and in the inferential section, Pearson's correlation coefficient test and multiple regression (step-wise) were used by the SPSS statistical software. The findings of the study indicated that there is a negative and significant relationship between social anxiety and its dimensions (fear of strangers, fear of evaluation by others, fear of speaking in public, fear of social isolation, fear of showing symptoms of anxiety) and academic performance. The results of the study showed that the components of fear of showing symptoms of anxiety and fear of strangers are the best predictors of the variable of academic performance.