Background and Aim: The aim of the present study was to investigate the the mediating role of Language Self-Motivational System in relationships between Personality Traits with English Anxiety in Students. Methods: The research method was descriptive-correlation based on structural equations. The statistical population of the present study consisted of all female high school students in the ninth grade of 10 public schools in the academic year 2021. In this study, 350 people as a sample size by two-stage cluster sampling method. Students were selected. To collect data from HEXACO Personality Traits Questionnaire (2013), Taguchi, et al’s Self-Motivational System Questionnaire (2009) and Khalaf Ali’s English Language Anxiety Questionnaire (2017) were used. Structural equations with SPSS18 and AMOS23 software were used to analyze the data. Results: Findings showed that personality traits and language self-motivational system have a direct effect on English language anxiety in students. Also, personality traits have a significant effect on English language anxiety through mediation of language self-motivational system in students. Conclusion: In general, the research model was approved and the research variables were able to predict 49% of the English language anxiety variable. The present study shows the importance of cognitive and motivational factors in explaining English anxiety.